central to Greek interests after the establishment of the patriarch's headquarters in 1461, shortly after Hagia Sophia was converted into a mosque). Patriarchate After the 1453 fall of Constantinople, when the Sultan replaced de jure the Byzantine Emperor for subjugated Christians, he recognized the Ecumenical Patriarch as the religious and national leader (ethnarch) of the Greeks and other ethnic groups in the Greek Orthodox Millet. The Patriarchate had primary importance, occupying this key role for Christians of the Empire because the Ottomans did not legally distinguish between nationality and religion and considered the empire's Orthodox Christians a single entity. The position of the Patriarchate in the Ottoman state encouraged Greek renaissance projects centering on the resurrection and revitalization of the Byzantine Empire. The Patriarch and his church dignitaries constituted the first centre of power for the Greeks in the Ottoman state, which infiltrated Ottoman structures and attracted the former Byzantine nobility. Merchant middle class The wealth of the extensive Greek merchant class provided the material basis for the intellectual revival featured in Greek life for more than half a century before 1821. Greek merchants endowed libraries and schools. On the eve of the Greek War of Independence, the three most important centres of Greek learning (schools-cum-universities) were in the commercial centres of Chios, Smyrna and Aivali. The first Greek millionaire of the Ottoman era was Michael "Şeytanoğlu" Kantakouzenos, who earned 60,000 ducats a year from his control of the fur trade from Muscovy. Civil servants During the 18th century, the Phanariots were a hereditary clerical−aristocratic group who managed the affairs of the patriarchate and the dominant political power of the Ottoman Greek community. They became a significant political factor in the empire and, as diplomatic agents, played a role in the affairs of Great Britain, France and the Russian Empire. The Phanariots competed for the most important administrative offices in the Ottoman administration; these included collecting imperial taxes, monopolies on commerce, working under contract in a number of enterprises, supplying the court and ruling the Danubian Principalities. They engaged in private trade, controlling the crucial wheat trade on the Black Sea. The Phanariots expanded their commercial activities into the Kingdom of Hungary and then to the other Central European states. Their activities intensified their contacts with Western nations, and they became familiar with Western languages and cultures. Before the beginning of the Greek War of Independence, the Phanariots were firmly