The Prophet Muhammad (PBUH) was born on Monday, 12th Rabi al Awwal, in the year of the elephant, c. 571, in Mecca. He was forty years old in 610, when on a night in the month of Ramadan, the angel Gabriel came and asked him to ‘Recite in the name of thy Lord who created man’. The Prophet (PBUH) migrated from Mecca to Medina in 622. This became the first year of the Muslim calendar, beginning with 16 July, as the first day of the first month. 

The Prophet Muhammad (pbuh) was a great prophet and a great general who possessed nine named swords, led his followers in eight major battles, and organized about a hundred raids inhis last ten years at Medina. He expelled Jewish tribes from Medina,Banu Qaynuqain February 624, Banu Nadir in August 625, and Banu Qurayza in March 627. And attacked the Jews of Khyber outside Medina in May/June 628. 

The Prophet dispatched an army in Jumada al-awwal 629, to take revenge for killing of his emissary at Mutah but all three of the commanders appointed by the Prophet were killed and Khalid ibin al-Walid brought back the army to Medina. The Prophet went to Mecca in triumph on 20 Ramadan 8/11 January 630 to become a Prophet (PBUH) with honour in his own country. Before he died at Medina on 13 Rabi al-Awwal 11/8 June 632, the prophet ordered an army to avenge the martyrs of battle of Mutah.

The Prophet’s elder father-in-law, Abu Bakr as-Siddiq, was proposed caliph (successor) by his younger father-in-law, Umar. On the first day of his caliphate, Abu Bakr ordered the army to fulfill the Prophet’s command and march to Mutah. Thereafter, Caliph Abu Bakr organized armies for the Ridda wars(wars of apostasy) against those who had turned away from prophet on his death, and established an Islamic state in Arabia. This enabled the Muslimsto create the largest pre-modern empirethat was planned by the Prophet Muhammad (pbuh), who had sent ambassadors to rulers of the states round him to accept Islam.

The first caliph, Abu Bakr (632-634), on his deathbed, nominated the Prophet Muhammad’s (pbuh)younger father-in-law, Umar Al-Farooq (634-644), as the second caliph who assumed office on 23 August 634.During the Ridda wars those who did not accept Islam and took up arms were killed or enslaved. Caliph Umar freed thousands of Bedouin Arab enslaved during the Ridda wars. He expelled Christians and Jews from Arabia, and occupied the most heavily Christian areas in the world. Jerusalem fell in February 638. Syria was conquered in 634-641, and Egypt in 639-642.

Persian empire comprising Iraq and Iran was conquered in 633-655. The Persian slaves in Medina chose a Persian slave, Firuz Nahavandi Abu Lulu, to attack Umar while he was leading the morning prayers at Al-Masjid al-Nabawi. He wounded Umar and twelve others. Six did not survive. Caliph Umar died three days later on Wednesday, 3rdNovember 644 (26thDhu al-Hijja 23). It was followed by rebellion all over conquered Persian Empire.

Caliph Umar nominated a council of six to elect his successor, who chose a first cousin of the Prophet, son of adaughter of Um Hakim bint Abdul Mutalib,and elder son-in-law of the Prophet, Usman AL-Ghani, known as Dhu al-Nurayn (of two lights), because he married to two daughters of the Prophet, firstly Ruqayyah and upon her death to Kulsoom. Caliph Usman consolidated the Islamic conquest and brought prosperity which created rivalry among the tribes. Caliph Usman (644-656), was surrounded by dissidents from Egypt, Kufa and Basra, and killed while he was fasting and reciting the Quran in his house at Medina, and another cousin of the Prophet, i.e. son of his father’s brother and the Prophet’s younger son-in-law, Ali (656-661), took over.

The failure of Caliph Ali to punish the murderers of his predecessor ran counter to the Quranic law of Qisas (Retaliation), and the traditional belief in tribal honour, which required every member of an Arab tribe to avenge the murder of one of their member, and stipulated that the heir was the man who accepted the responsibility for avenging the death. Muawiya, who was brother-in-law of the Prophet Muhammad (PBUH), leader of the Banu Umayya and the Governor of Syria, demanded that murderer of Caliph Usman be punished. This led to the di­vision of the caliphate. Caliph Muawiya ruled the western part of the caliphate from Damascus in Syria, while Caliph Ali ruled the eastern part of the caliphate from Kufa in Iraq.

The Kharijites (seceders), partisan of Ali’s party did not agree with the division. They decided to kill both the caliphs on the same day during the early morning prayers. Caliph Muawiya in Damascus escaped with minor injuries, but Caliph Ali in Kufa received fatal injuries and died on 21stof Ramzan /26 January 661. Ali’s elder son Hasan fulfilled Qisas by killing Ali’s murderer and was declared caliph as successor of Ali butentered into a pact with Caliph Muawiya, whereby he gave up the caliphate on 10 August 661, in fulfillment of a saying of the Prophet Muhammad’s (PBUH), ‘This son of mine is a Sayyid, and he will unite two branches of the Muslims’. In celebration of this meri­torious deed of reconciling the opposing parties, the year is known as ‘Am al-Jama’a, the Year of Community (Jafri, 1979, 156). Imam Hasan died nine years later at Medina in AH 49/AD 669.

Under the Umayyad caliphate (661-750), Muslim armies conquered all of Christian North Africa, Spain, Portugal, Andorra and part of France.In the east, theyconquered Bukhara and Samarqand in 706–712, and Sindh in 711-714.

The successful challenge to the Umayyad’s came as per the tribal system from the family of Abbas who was uncle of the Prophet (PBUH), and eldest male member of the Prophet’s family at the time of his death. It was natural for an Arab to accept Abbas as heir to the Prophet (PBUH), because the eldest male of the tribe was considered by them to be the main recipient of the inheritance. The claim of Abbas’s family also received support from the offspring of younger brother of Hasan and Husain named Muhammad, who was a son of Caliph Ali from ‘a blackish slave girl from Sindh’ (Ibn Saad, Book V, 105). He was known as Ibn Hanafiyya, to distinguish him from another son of Caliph Ali by that name from another wife. The imamate of Muhammad, son of Caliph Ali, and after his death that of Abu Hashim, son of Muhammad, was recognised by Shiites in preference to those members of the family of Caliph Ali who had taken to political inactivity and prayers. As Abu Hashim had no son, he made Muhammad, an offspring of Abbas, his nominee to the imamate and gave him letters addressed to Shiite circles in Khurasan. 

This Muhammad, a great grandson of Abbas, conceived a plan for seizure of power from the Umayyad’s, which upon his death in 743, was put into operation by his son Ibrahim. It received active support in the province of Khurasan where Abu Muslim, a non-Arab, unfurled the black banner of the Abbasids in June 747 and occupied the provincial capital Merv (now in Turkmenistan). As Ibrahim had been captured in 748 and had died in captivity, his brother Abu al-Abbas al-Saffah received the oath of allegiance as caliph in the mosque of Kufa on 28 November 749.

Although Abbasids tried to kill the entire Umayyad family, Abd ar-Rahman, escaped and established an independent kingdom in 756 in Andalusia (Spain) where most of the local population converted to Islam by the tenth century. 

Muslim forces captured part of Sicily in 827sacked the Basilicas of Saint Peter and Saint Paul in Rome in 846, and sacked Pisa in 1004 in Italy.

Instead of militia of Arab warriors who were riddled with factions, the Abbasid caliphs began to hire slave troops.The Shia Buyid troops from Daylam (on the southern shore of the Caspian Sea) employed by the Abbasids kept control of Baghdad for over a century. And independent dynasties emerged in the East, like the Tahirids, Saffarids, Samanids and Ghaznavids. A Shiite Fatimid caliphate (909-1171) came into power in North Africa, and built their capital al-Qahirah (Cairo) in 973.

In 1055, the Sunni Seljuq Turks under Tughril Beg (1016-1063) took control of Baghdad fromtheShi'aBuyids.The Seljuq Alp Arslan added  Armenia and Georgia in 1064, invaded the Byzantine Empire in 1068 and at the Battle of Manzikert in 1071, annexed almost all of Anatolia. His famous vazir, Nizām al-Mulk established a network of madrassas (Islamic schools) in BaghdadIsfahanNishapurMosulBasra, and Herat,capable of giving uniform training to the state’s administrators and religious scholars, and wrote a treatise on kingship titled Siyasatnama (The Book of Government).  He appointedAbū Ḥāmid Muḥammad ibn Muḥammad al-Ghazālī(405-505/1058 –1111) as head of the Nizamiyyamadrassa in Baghdad. Al-Ghazali wrote more than 70 books on science, philosophy and Sufism.He wrote Tahafut al-Falasifa(The Destruction of Philosophy), as he saw in philosophy a danger to correct faith. Al-Ghazali’s work, Ihya al-Ulum al-Din(The Revival of the Religious Sciences), provided the parameters within which a revived Islam was confined. He brought orthodox Sunni theology and Sufi mysticism together. To him the ultimate value was only in the mystical experience (nubuwwa)that is attained as a result of followingSufipractices.Thus Muslim world moved toward an increasingly theologically enclosed culture that could no longer promote original scientific research, while Europe was once again becoming aware of the glorious heritage of Greek science and philosophy.

The majority of Muslims believe that the Prophet Muhammad (PBUH) did not appoint a successor, and regard the first four caliphs, Abu Bakr, Umar, Usman and Ali as close companions of the Prophet and the rightly guided caliphs.

However today about 13% Muslims are Shi’atu Ali (partisan of Ali) who believe that the Prophet Muhammad (PBUM) nominated  his cousin and son-in-law Ali  as his successor.

 A majority of Shias, about 85 percent are Twelvers who believe that after the death of elder son of Imām  Ja'far al-Sadiq (702–765), his younger surviving son Musa al-Kazim became Imam and his descendent the twelfth and final imam is Muhammad al-Mahdi.

The Zaidiyyah Shias believe that a true imam must fight against corrupt rulers, therefore Zayd was the rightful 5th imam since he was killed fighting tyranny and corruption.

Batiniyyah Sevener believe that Isma'il  (721–755), the predeceased elder son of Ja'far al-Sadiq (702–765) was the divinely appointed 6thImamwho was succeeded by his son, Muhammad ibn Ismail, as the 7th Imam, who became "hidden" and will return as the Mahdi. The Assassins,Druses,FatimidsIsmailisand Qarmatians, areIsmailiSeveners.

The Qarmatiansbelieve that the Imams are in occultation, who communicate and teach their followers through a network of dawah(Missionaries).The Qarmaṭians considered the pilgrimage to Mecca a superstition. They sacked Mecca and Medina in 930, and desecrated the Zamzam Well with corpses of Hajj pilgrims and took away the Black Stone from Mecca.

The Nizari Mawla of Alamut, Hassan-i Sabbah (1034-1124) founded a group of fedayeenknown as Hashshashin, or Assassins who assassinatedthe Seljuq vazir Nizam al-Mulk on 10 Ramadan 485 A.H.(14 October 1092). The Seljuq ruler Malik Shah (1072-1092) was assassinated the same year, which resulted in a war of succession and dismemberment of the Seljuk Empire.

The Pope Urban II at the town of Clermont called the first crusade by Christians against Muslims in November 1095in central France, which was to depart on 15 August 1096. The pope made the proposal: 'Whoever for devotion alone, but not to gain honour or money, goes to Jerusalem to liberate the Church of God can substitute this journey for all penance.' The reaction to Pope's appeal was astounding as thousands saw this as a new way to attain salvation and to avoid the consequences of their sinful lives.

However, before that Peter the Hermit, led a "People's Crusade" of about 20,000 people towards the Holy Land after Easter 1096. The Seljuqs easily defeated the untrained People's Crusade. They ambushed them outside Nicaea with only about 3000 people escaping.But they could not stop the progress of the army of the subsequent Princes' Crusade,which set off from France and Italy on 15 August 1096.They took the city of Nicaea in June 1097. The first Crusader State, the County of Edessa, came into being under Count Baldwin of Boulogne in 1098.

 In 1099 the crusaders captured the Holy Land and established three more states: those of Jerusalem, Antiochand Tripoli, andbegan to take control of the coastline with the support of the Italian trading cities.

 The Seljuqs appointed Imad ad-Din Zengiof Oghuz Turk origin as atabeg(governor) of  Mosul in 1127.Hecaptured Edessa on 24 December 1144, which was the first city to fall to the Crusaders, and became the first to be recaptured by the Muslims. 

The news of this disaster prompted Pope Eugenius III to issue an appeal for the second crusade (1145-49).King Louis VII of France and King Conrad III of Germany led armies from France and Germany to Jerusalem and Damascus without winning any major victories.

After the assassination of Imad ad-Din Zengi in 1146, his sons Saif ad-Din Ghazi Iand Nur ad-Din, divided the kingdom between themselves. In 1149, Nur ad-Din defeated Raymond, Prince of Antioch, seizing several crusader castles in the north of Syria, defeated an attempt by Joscelin II to recover the County of Edessa, and captured Damascus.

In 1163, Shawar, the vazir to the Fatimid caliph al-Adid, askedfor Nur ad-Din’s help against his rival Dirgham. Nur ad-Din sent his Kurdish commander Shirkuh, who restored Shawar as Vazir but kept the control of Egypt. Shawar was dissatisfied and asked Amalric, crusader king of Jerusalem, for help. Christian Amalric and Shia Shawar besieged Sunni Shirkuh at Bilbeis. Shirkuh retreated to Alexander where he left his nephew Saladin to guard the city. To relieve Shirkuh, Nur-ad-Din moved against the crusader state of Antioch. Amalric went back so did Shirkuh and Shawar was left with Egypt.

Shirkuh returned in 1166 to take back Egypt. Once again the Crusader King of Jerusalem came to Shawar’s aid. Saladin helped his uncle Shirkuh to move to Alexandria where the besieged Shirkuh agreed to leave Egypt alone in return for a Crusader withdrawal. Amalric left with a favorable treaty resulting in Egyptian tribute to Jerusalem and a friendly Shawar in control.

Amalric launched an attack against Bilbeisin1168, Shawar appealed to Damascus and Shirkuh returned and fought off Amalric. The Fatimid vazir, Shawar, was assassinated and Shirkuh died in 1169. Saladin took over as vazir of the Fatimid Caliph, al-Adid. However, a group of Egyptian soldiers and amirs attempted to assassinate Saladin,and 50,000 black African soldiers from the regiments of the Fatimid army opposed Saladin's rule. Saladin crushed the uprising by 23 August 1169 and after that he never again had to face a military challenge from Cairo.

Towards the end of 1169, Saladin, with reinforcements from Nur ad-Din, defeated a massive Crusader-Byzantine force near Damietta. In 1170, Nur ad-Din sent Saladin’s father to Egypt at his request, as he had begun granting his family members high-ranking positions to strengthen his support base. Saladin also ordered the construction of a college for the Maliki branch of Sunni Islam in the city, and one for the Shafi'i denomination to which he belonged in al-Fustat.

After establishing himself in Egypt, Saladin launched a campaign against the Crusaders besieging Darum in 1170.  He also attacked and captured the Crusader castle of Eilat, built on an island off the head of the Gulf of Aqaba

Nur ad-Din wrote to Saladin in June 1171, to establish the Abbasid caliphate in Egypt. Fatimid caliph Al-Adid died on 13 September 1171, and five days later, the Abbasid khutba was pronounced in Cairo and al-Fustat, proclaiming al-Mustadias caliph. When Nur ad-Din diedin 1174, Saladin took over Damascus and proceeded to reduce other cities previously held by Nur ad-Din. The combined forces of Mosul and Aleppo marched against Saladin who won and proclaimed himself king. The Abbasid caliph declared him "Sultan of Egypt and Syria." Saladin received threats from the Ismaili "Assassins", led by Rashid ad-Din Sinan.On 11 May 1175 a group of thirteen Assassins gained admission into Saladin's camp, but were detected and killed. Once while Saladin was resting in one of his captain's tents, an assassin rushed forward at him and struck at his head with a knife. Saladin had his guards supplied with link lights and had chalk and cinders strewed around his tent outside Masyaf—which he was besieging—to detect the Assassins. One night Saladin's guards noticed a spark glowing down the hill of Masyaf and then vanishing among the Ayyubid tents. Saladin awoke to find a note pinned by a poisoned dagger. The note threatened that he would be killed if he didn't withdraw. Saladin made an alliance with Sinan and his Assassins and left for Egypt. 

Saladin returned in November 1177 to fight crusaders. Saladin and his men were surprised near Ramla on 25 November and suffered heavy losses. Saladin won a victory in the spring of 1178, at Hama. He ordered one of his generals, Farrukh-Shah, to guard the Damascus frontier with a thousand men, retire in case of attack, avoiding battle, and light warning beacons on the hills. In April 1179, the Crusaders led by King Baldwin expecting no resistance, advanced in pursuit of Farrukh-Shah's force, and were defeated by the Ayyubids. In the spring of 1180, while Saladin was in the area of Safad, to commence a campaign against the Kingdom of Jerusalem, King Baldwin sent messengers to him with proposals of peace. Saladin agreed to a truce. Raymond of Tripoli denounced the truce but was compelled to accept after an Ayyubid raid on his territory and the appearance of Saladin's naval fleet off the port of Tartus.

Raynald of Châtillon, harassed Muslim traders and pilgrimswith a fleet on the Red Seaand threatened to attack the holy cities of Mecca and Medina. In retaliation, Saladin besieged Raynald's fortressKerak in 1183 but was forced to leave on arrival of a relief force under King Baldwin IV. Saladin returned to Kerak again in 1184 with the same result. 

In late May 1187, Saladin assembled the largest army he had ever commanded, around some 30,000 men including about 12,000 regular cavalry. The opposing Crusader army consisted of around 20,000 men, including 1,200 knights from Jerusalem and Tripoli and 50 from Antioch. Saladin annihilated the Crusader force led byGuy of LusignanKing Consort of Jerusalem and Raymond III of Tripoliat the Battle of Hattin on4 July 1187, and. It was a major disaster for the Crusaders and a turning point in the history of the Crusades.The Christian cities surrendered one by one; Jerusalem surrendered on October 2, 1187 after 88 years with Christians. Only some of the ports remained with the Christians.

The Pope Urban III was said to have died of a heart attack at the news and his successor, Gregory VIII, issued an emotive crusade appeal and the rulers of Europe began to organise their forces for third crusade (1189-1192). Frederick Barbarossa's German army successfully defeated the Seljuq Turks in Asia Minor only for the emperor to drown crossing a river in southern Turkey and Saladin escaped facing this formidable enemy. 

The Franks in the Levant had managed to cling onto the city of Tyre and were besieging the most important port on the coast, Acre. It was here in the summer of 1190 that Philip Augustus and Richard the Lionheart landed. The city surrendered and Philip returned home. 

The armies of Saladin faced the army of King Richard at the Battle of Arsuf on 7 September 1191, and suffered heavy losses. Richard occupied Jaffa, restoring the city's fortifications. Saladin moved south, where he dismantled the fortifications of Ascalon to prevent it, from falling into Crusader hands.

In October of 1191, Richard began restoring the inland castles on the coastal plain beyond Jaffa in preparation for an advance on Jerusalem. During this period, Richard and Saladin passed envoys back and forth, negotiating the possibility of a truce. Richard proposed that his sister, Joan of England, Queen of Sicily, should marry Saladin's brother and that Jerusalem could be their wedding gift However, Saladin rejected this idea when Richard insisted that Saladin's brother convert to Christianity

In January 1192, Richard's army occupied Beit Nuba, just twelve miles from Jerusalem, but withdrew without attacking the Holy City. Instead, Richard advanced south on Ascalon, where he restored the fortifications. In July of 1192, Saladin tried to threaten Richard's command of the coast by attacking Jaffa. Saladin very nearly captured it, however, Richard arrived a few days later and defeated Saladin's army in a battle outside the city.

The Battle of Jaffa (1192) proved to be the last military engagement of the Third Crusade. After Richard reoccupied Jaffa and restored its fortifications, he and Saladin again discussed terms. At last Richard agreed to demolish the fortifications of Ascalon, while Saladin agreed to recognize Crusader control of the Palestinian coast from Tyre to Jaffa. The Christians would be allowed to travel as unarmed pilgrims to Jerusalem. Saladin died of a fever on 4 March 1193, at Damascus,not long after King Richard's departure.

The Fourth Crusaders (1201-1204) came to an abrupt halt as the Pope Innocent III excommunicated the entire Crusade for attacking and looting Constantinople, the greatest Christian city in the world.

In the Fifth Crusade (1217-1221), the Crusaders attacked Egypt from both land and sea, but became bogged down outside the port of Damietta. 

In the Sixth Crusade in 1229, Emperor Frederick IIachieved the peaceful transfer of Jerusalem to Crusader control through negotiation with Kamil. The Muslims took back Jerusalem a decade later. 

This prompted the Seventh Crusade (1239-41), led by Thibault IV of Champagne who recaptured Jerusalem but it was lost again in 1244. 

In 1249, King (later Saint) Louis IX of Franceled the Eighth Crusade against Egypt, which ended in defeat. 

In 1250, when the Ayyubid sultan as-Salih Ayyub died, his Mamluk slaves murdered his son and heir al-Muazzam Turanshah, and Shajar al-Durr the widow of as-Salih became the Sultana of Egypt. She married the Atabeg (commander in chief) EmirAybak and abdicated, Aybak ruled from 1250 to 1257.

When Mongke Khan was installed as the Great Khan in 1251, he selected his brother, Hulagu, to conquer the Muslim states. Hulagu's Mongol army set out for Baghdad in November 1257 and laid siege to the city on January 29, 1258. Baghdad surrendered on 10 February 1258. 

In 1260, Hulagu demanded that Mamluk Sultan Saif ad Din Qutuz in Cairo should surrender. However, Mongke Khan died and Hulagu had to return to Mongolia for the election of a new Khan. Upon receiving news of Hulagu's departure, Sultan Qutuz quickly assembled a large army in Cairo, which defeated the Mongols at Ayn Jalut, where David had once humbled the giant Goliath.

On way back to Cairo, Sultan Qutuz was assassinated and Abu al-Futuh (Father of conquests) Bai (chief) bars(panther)took over as Sultan of Egypt, a move which was contested by Sinjar al-Halabi whoclaimed Damascus. Baibars defeated Sinjar on 17 January 1261 and occupied Damascus, thereafter the Ayyubid Amirs of Homs and Hama who had staved off the Mongols also submitted to him. When the Abbasid refugee Abu al-Qasim Ahmad, the uncle of the last Abbasid caliph al-Musta‘sim, arrived in Cairo in 1261, Baibars had him proclaimed caliph as al-Mustansir II and duly received investiture as sultan from him. Unfortunately al-Mustansir II was killed in an expedition to recapture Baghdad from the Mongols. In 1262, another Abbasid who had survived from the defeated expedition, was proclaimed caliph as al-Hakim I.In 1263, Baibars laid siege to Acre, the capital of the remnant of the Kingdom of Jerusalem. He used siege engines to defeat the Crusaders in battles such as the Fall of Arsuf from March 21 to April 30. He next captured Athlith and Haifa. In 1266, Baibars invaded the Christian country of Cilician Armenia. In 1268, he besieged Antioch, capturing the city on 18 May. 

In the Ninth Crusadein 1270, Prince Edward of England arrived in Acre in May 1271 who survived an assassination attempt organised by Baibars, negotiated a ten-year truce and returned to England in 1272.

In 1272 Baibars invaded the Kingdom of Makuria, headed by King David I. Baibars' invasion of Makuria continued for four years until by 1276, Baibars had completed his conquest of Nubia,  including the Medieval lower Nubia which ruled by Banu Kanz.

In 1277, Baibars invaded the Seljuq Sultanate of Rûm, then controlled by the Mongol Ilkhanate . Baibars died in Damascus on 1 July 1277.

In 1291, Acre, the last major Crusader fortress in the Holy Land fell to the forces of the Mamluk Sultan, al-Ashraf Khalil of Egypt, and any remaining territories on the mainland were lost over the next decade.

One product of the Crusades and the Mongol invasion was Taqi ad-Din Ahmad ibn Taymiyyah (1263-1328). Ibn Taymiyyah’s family had to leave their hometown of Harran which was completely destroyed by the Mongols and settle in Damascus. After the death of his father in 1284, he took his place as the head of the Sukkariyya madrassa giving lessons on the Hadith. A year later, as chair of the HanbaliZawiyaat the Umayyad Mosque, he started teaching tafsiron Fridays.

In 1293, Ibn Taymiyyah issued a Fatwa saying that any person, Muslim or non-Muslim, who insulted Muhammad must be killed. In 1310, Ibn Taymiyyah wrote against visiting the tombs of prophets and saints. According to Ibn Taymiyyah, seeking the assistance of God through intercession is allowed, as long as the other person is still alive. But those who ask assistance from the grave of the Prophet or saints, are engaged in shirk.

To Ibn Taymiyyah, the role models for Islamic life were the first three generations of Islam (Salaf); which constituted Muhammad's companions, the Sahaba (first generation), followed by the generation of Muslims born after the death of Muhammad known as the Tabi'un(second generation) and then the generation after the Tabi'un known as Tabi' Al-Tabi'in(third generation). Any deviation from their practice was bid‘ah (innovation), and was forbidden by Ibn Taymiyyah.

Ibn Taymiyyah wrote that, "It is in jihad that one can live and die in ultimate happiness, both in this world and in the hereafter. Abandoning it means losing entirely or partially both kinds of happiness." He believed in taking the initiative in fighting those who did not observe unambiguous obligations and prohibitions, until they undertook to perform the prescribed prayers, to pay zakat, to fast during the month of Ramadan, and to make the pilgrimage to Mecca. He made a declaration of apostasy (takfir) against a Muslim who did not obey Islam, and considered it a duty to oppose and kill Muslim rulers who did not implement the revealed law (shari'a). He declared the Mongol ruler Ghazan and other Mongols who did not accept shari'a in full, to be unbelievers. Ibn Taymiyyah affirmed that Jihad against the Mongols, "was obligatory, because the latter ruled not according to Sharīʿah but through their traditional, and therefore man made, Yassacode. He called for a defensive jihad to mobilise the people to kill the Mongol rulers and anyone who supported them, Muslim or non-Muslim. According to Ibn Taymiyyah, everyone who was with the Mongols, in the state over which they ruled had to be regarded as belonging to the most evil class of men. He was either an atheist (zindīq) or a hypocrite who did not believe in the essence of the religion of Islam. This meant that he outwardly pretended to be Muslim but belonged to the worst class of all people who were the people of the bida` (heretical innovations).

 Ibn Taymiyyah thought of the Alawites as heritical and campaigned against Shias. He considered Husain's martyrdom a divinely bestowed honour—not a tragedy, and that the Islamic response to such loss is not extravagant mourning but to endure the loss with patience and trust in God. 

Ibn Taymiyyah also criticized Mutakallimun for their use of kalam, rationalist theology and philosophy. To Ibn Taymiyyah the usul al-din of the Mutakallimun, deserved to be named usul din al-shaytan (principles of Satanic religion).

According toIbn Taymiyyah, Tauheed is the most essential element of Islam. It means one nation under one Allah, i.e. Khilafat. The Prophet Mohammed (pbuh) established the Islamic state according to the Quran, performing the political and religious duties simultaneously. Muslim fragmentation is because of the loss of a sacred central authority of Khalifah, where the government is established according to the commandments of Quran, with Allah being the supreme and sovereign ruler of the state. Man cannot be the sovereign.

Meanwhile, more than half of the European portion of what is now Russia and Ukraine, were under the suzerainty of Muslim Tatars and Turks from the 13th to 15th centuries.Between 1354 (when the Ottomans crossed into Europe at Gallipoli) and 1526, they had conquered the territory of present-day Greece, Bulgaria, Romania, Albania, Serbia, Macedonia, Montenegro, Bosnia, and Hungary. The Ottomans conquered Thraceand much of Macedoniain 1371. The Bulgarian capital Sofiafell in 1382. Sultan Mohammad conquered Constantinople in 1453. All of Greecefell in 1461 and much of Serbiaby 1459. They laid siege to Vienna in 1683. Today, the Muslim-majority regions of Europe are Bosnia and HerzegovinaAlbaniaKosovo, parts of BulgariaMacedonia and Montenegro, as well as some  Russian regions in Northern Caucasus and the Volga region. 

In 1517, Ottoman Sultan Selim I defeated the Mamluks and made Egypt part of the Ottoman Empire.The Abbasid Caliph Al-Mutawakkil III was captured and transported to Constantinople. He formally surrendered the title of caliph as well as its outward emblems — the sword and mantle of Muhammad— to Ottoman Sultan Selim I. Thus the Ottomans established the caliphate (1517-1925) in Turkey.

The Mediterranean naval campaign, which lasted from 1570 to 1573, resulted in the Ottoman control of much of the Mediterranean Sea, which was once called by the Romans Mare Nostrum(Latin, "Our Sea"). Further, the Barbary piratesof North Africa based primarily in the ports of SaléRabatAlgiersTunis, and Tripoli,under Ottoman rule preyed on Christian shipping in the Western Mediterranean, and captured 1 million to 1.25 million Europeans as slaves from the 16thto 19thcentury.

Thus, in about nine hundred years, Muslim armies had encircled, captured and invaded Christian Europe from all sides but the north. From Spain in the west, they attacked France, from the Mediterranian in the south they attacked Italy and from Turkey in the East, they attacked Vienna. According to an estimate in 2012, one out five people in the world were Muslim (22.32%), making Islam the second-largest religion in the worldafter Christianity (31.50%).