An important dynasty that traces its origins to Uthman, the leader of a Turkic clan who moved to the borders of Byzantine empire having fled the Mongul invasion in the thirteenth century A.D. A strong military organization was established and by 1453 A.D. the Ottomans had taken over what remained of the Byzantine Empire, making Constantinople their capital, Istanbul. By the sixteenth century A.D. they ruled all of modern Turkey, the Balkans, much of North Africa and the Middle East. Although the Ottomans continued to be a major power until the nineteenth century A.D., they had already started losing land to local leaders in Europe and the Middle East. Joining the First World War was a destructive blow leading to the loss of the rest of its Arab provinces. Its end was at the hands of the movement of the Young Turks led by Ataturk in 1922 A.D. The Ottoman dynasty can thus be divided into three stages. The first, from the thirteenth century A.D. until the capture of Constantinople represents a period of growth from a small sovereignty to a major dynasty. From 1453 A.D. to the mid-sixteenth century A.D. is considered the grand Ottoman period of superior developments in technology and arts. The last period, was that of the decline which started in the mid-sixteenth century A.D. until its end in 1922 A.D. The Ottomans left a rich architectural legacy for they had built extensively, particularly in their imperial cities, establishing a recognized Ottoman architecture known for its tall pointed minarets, multi-leveled domes and tilework. They were also great patrons of the arts, where Iznik tiles, carpets and textiles are among their most celebrated artistic legacies.