Before it disappeared, the island, just 1 square mile (2.5 square kilometers) in area, was the site of a monastery built by a Byzantine patriarch named Photius I, in 886. Photius had been banished to the island by Byzantine Emperor Leo VI, because of accusations that Photius had participated in a conspiracy against Leo's predecessor, Basil I [source: Atherton].
After researchers identified the site from ancient maps, divers photographed the underwater ruin. Ali Kılıç, mayor of the Istanbul district of Maltepe, told a Turkish newspaper that he hoped the island would be recognized by the United Nations and earn a spot on its World Heritage List [source: Anadolu Agency].
In 2016, just a few visual traces of the island can be spotted — flashes of light on the water over it, which are caused by reflections from the top of the sunken monastery. But archaeologists hope to uncover more.