often used as a haven for the local Greek population when plague hit the mainland. Another monastery, built in the late 19th century and dedicated to Hagios Spyridon, is in ruins. Mavromatakis Köşkü, a house belonging to İsmet İnönü, the second President of Turkey who was a regular visitor to the island, is sometimes open as a museum. In the centre of Halki Town is the Greek Orthodox church of Hagios Nikoloas (St Nicholas), built in 1857 on the site of an older Byzantine church. It contains a spring (ayazma) dedicated to Hagia Paraskevi. Nearby are the Ben Yazkor synagogue and Heybeliada Cami, their proximity recalling more cosmopolitan times. Like Büyükada, Heybeliada has many fine 19th-century mansions especially on Lozan Zeferi and Refah Şehitler Streets. They are all listed in John Freely's book on the islands.Published in 2006 Mary Ann Whitten's book, An Island in Istanbul: At Home on Heybeliada, recounts the story of an American couple who bought one of the old houses to live in. The Halki Seminary On Ümit Tepesi (Hope Hill) in the centre of the island is the Greek Orthodox monastery of Hagia Triada (; "Monastery of the Holy Trinity"). Its origins are shrouded in mystery but it was restored by patriarch Photios I of Constantinople who was buried there in the 9th century. The monastery was destroyed in 1453 but rebuilt and given an extensive library in 1550. It burned down again in 1821, and was finally reconstructed by patriarch Germanus IV of Constantinople in 1844 when it became home to the Halki Theological Seminary () of the Ecumenical Patriarchate of Constantinople, the main Greek Orthodox seminary in Turkey. In 1894 it was again destroyed, this time by an earthquake, only to be rebuilt two years later by Perikles Photiades. The Seminary has had a very chequered history and in 1971, parts of Turkey's Private University Law were ruled unconstitutional by the Constitutional Court, forcing all private institutions of higher education to become parts of state universities or close down. Halki's Board of Trustees refused to let it become part of the University of Istanbul so the seminary was shuttered. Its closure made it impossible to train any more Greek Orthodox clergy within Turkey and has proved very controversial, with President Erdoğan suggesting in 2021 that it might be reopened independently if Greece improved conditions for the Turkish Muslim population of Thrace. Famous Residents