Europe has an area of 10 million square-kilometers, and it ranks the fifth of the world's continents by surface area, followed by the Australian continent. Europe is an irregular-shaped peninsula. It is bounded to the north by the Arctic Ocean, to the west by the Atlantic Ocean, to the south by the Mediterranean Sea, and to the east by Asia.
Islam reached Europe, from the East, through the repeated endeavors by Muslims to conquer Constantinople since the Chilaphate of Mu‘aawiyah ibn Abi Sufyaan, May Allaah Be Pleased with him, [41-60 AH]. As for the west of Europe, the great Muslim leader Taariq ibn Ziyaad conquered Al-Andalus in 91 AH/ 710 AD. Muslims conquered the inner parts of the Andalusian Peninsula and crossed it to conquer France. Muslim armies crossed the Pyrenees [a range of mountains in southwest Europe that forms a natural border between France and Spain], and advanced to the north, consolidating their hold on southern France until they arrived at Poitiers, a French city on the Clain River in west central France. Poitiers witnessed the Battle of Poitiers, also known as the Battle of Tours in 114 AH / 723 AD, in which the Muslim army was heavily defeated and many of them were killed. This battle marked the end of the Muslim advance in Western Europe.
The Aghlabid Dynasty that ruled Tunisia managed to conquer the southern side of the European continent. They conquered the island of Sardinia in 95 AH / 810 AD, then the island of Crete. Then, Asad ibn Al-Furaat led the Muslim fleet to conquer the island of Sicily, which was the southern outlet for Central Europe, in 212 AH / 827 AD. Palermo was conquered in 216 AH / 831 AD.
The fighting Italian cities sought the help of Muslims to dislodge their rivals. This made it easy for Muslims to control some coastal parts of Italy. The Muslim advance even forced Pope John VIII to pay the Jizyah to the Muslims in 484 AH / 872 AD, after threatening to conquer the city of Rome itself. The island of Sicily was the main trade route between North Africa and Europe, as well as a cultural contact center that held a high degree of importance to both Muslims and Europeans.
However, Al-Andalus remains the most important contact center between the Muslim and European civilizations. It was the beacon of enlightenment in Western Europe. The city of Toledo that was seized by Spaniards in 478 AH/1085 AD became a vital source of enlightenment in Western Europe through which sciences were translated from Arabic into Latin then introduced to Europe. It was a lighthouse for seekers of knowledge from all over western and central Europe. Toledo remained for nearly four centuries, the major cultural and religious center in the Iberian Peninsula (Al-Andalus).
As we mentioned before, Muslims tried to conquer south-eastern Europe through Constantinople since the 1st Hijri century. Constantinople (now) was later conquered by the great Muslim leader Muhammad Al-Faatih in 857 AH / 1453 AD.
He deserved the praise of the Prophet, sallallaahu ‘alayhi wa sallam, who had said: "Constantinople would be conquered; the best prince is its prince and the best army is that army.” [Al-Haakim and At-Tabaraani; Al-Albaani: Dha‘eef]
Muhammad Al-Faatih made Constantinople the capital of his state and named it Islambul, which means the house of Islam. It was changed later to be Istanbul. Constantinople or Istanbul continued to be the capital of the Islamic State until the fall of the Ottoman Empire.
Thanks to the Ottoman Caliphate, the center of Europe was conquered when the Ottomans conquered the Balkans in 756 AH/ 1355 AD and all Central European countries became under the dominance of the Islamic Caliphate one after the other. Bulgaria was conquered in 774 AH/ 1372 AD, Serbia was conquered in 788 AH / 1386 AD, Bosnia and Herzegovina were conquered in 792 AH/ 1389 AD. Albania, Croatia and Belgrade and the country of Hungary were also conquered by the Ottoman Empire.
The Ottoman armies, under the leadership of Sultan Sulaymaan Al-Qaanooni, reached the walls of Vienna and besieged it in 936 AH/1529 AD), but failed to conquer it. There was another attempt to conquer Vienna after more than a hundred and fifty years, in 1094 AH/1683 AD during the reign of Sultan Muhammad IV, but again they failed to conquer the city.
Most of these lands remained under the dominance of the Ottoman Caliphate throughout its golden years, but as soon as the Caliphate started to wane, the Ottoman Empire gradually lost control over all the conquered European countries. By the year 1337 AH/ 1918 AD, the Ottoman Caliphate had no European lands left but the city of Istanbul. Being under Islamic rule for a very long time, many European areas became Muslim-majority countries, such as: Macedonia, Albania, Bosnia and Herzegovina, Montenegro, and large Muslim communities in Bulgaria and Romania.
The reason behind the conversion of most of the residents of the territories which were conquered by the Ottomans into Islam was the good and civilized treatment they received from Muslims. Justice and equality prevailed so that a poor villager was able to rise to the highest and most powerful positions in the Ottoman Empire. Such social equity and justice were not possible in other European communities that were contemporary to the Ottoman Empire. Peace was maintained in this area that was once a place of conflict and chaos. Europe benefited from the precise order of the Turkish military as well as the administrative systems that essentially depended on efficiency.
The People of the Book, Christians and Jews, in these areas that were ruled by the Ottomans for several centuries, enjoyed the kind treatment of Muslims that was evident in allowing these minorities to practice their religions freely. The evidence of this is that these people retained their religions, languages, and cultures. On the contrary, when the Spanish captured Al-Andalus in 897 AH/ 1492 AD, they evacuated the Muslim to North Africa and the Arab Orient. The few Muslims who decided to stay in Al-Andalus suffered from fanaticism, intolerance and persecution under the reign of the unfair Spanish rule. Eventually they were forced to convert to Christianity under the pressure of the Spanish Inquisition courts, which were set for them everywhere.