The politico-economic and political circumstances of the non-Muslim population of the Ottoman Empire following Sultan Mehmet II's conquest of Istanbul in 1453 have always been a major topic of research. During the early periods of the Ottoman Empire, non-Muslims were granted certain rights, but they were also banned from certain activites such as building new churches. At the end of the 18th and throughout the 19th centuries, the changing world order allowed non-Muslims to be granted new rights of a wider variety. During this period the Greek Orthodox community, which became powerful economically, built new religious structures almost everywhere around the Anatolian region. There are very few scientific studies carried out on these structures. Following the Lausanne Treaty in 1923 most of this Greek population had to emigrate to Greece, and today many of these religious structures remain abandoned.