Excerpt:
The history of Islam in Germany is believed to date back to the Caliph Harun al-Rashid. In the fabled tales of "1001 Nights," al-Rashid is said to have wandered the streets of Baghdad at night dressed as a merchant in order to learn about the needs of his subjects. Various sources relate that Charlemagne established diplomatic relations with this Abbasid ruler in the year 797 or 801. Both sides reportedly guaranteed freedom of belief for members of the other religion in their respective empires. It is in any case an established historic fact that the elephant Abul Abbas died in 810. This magnificent animal had been sent by the caliph to Charlemagne in Aachen as a token of his friendship.
The Spread of Islam in Europe
At the time of Charlemagne, most of the Iberian Peninsula was already under the control of the Moors
Between the 8th and 10th centuries, Arab Muslims carried out raids on Corsica, Sardinia, Sicily and even Rome. Islamic forces advanced from the south and the west via Piemont and Burgundy into the Rhone Valley. They occupied alpine passes and parts of Switzerland, where they remained from 952 to 960.
The last great onslaught came from the east. When the Ottoman Turks captured the Byzantine capital Constantinople (today Istanbul) in 1453, it spelled the end of the Eastern Roman Empire and this final bastion of Christianity in Asia Minor. Afterwards, the Ottomans expanded their realm of influence and made incursions in 1529 and 1683 throughout the Balkans and as far as the gates of Vienna, and Islamized Bosnia and Albania.