The island of Sedef is the smallest island of the islands open to settlement. 1300X1100 meters in size. The vegetation on it is called Sedefadasi because it is compared to psoriasis when viewed from a distance. Since the rabbit was abundant in the past, the name Rabbit-Ventil was also used. In Sedefadasi, like other Istanbul islands, it was used as a place of exile during the Byzantine period. One of the most important exiles of the island is Patriarch ignatios, whose militia was sent to the island in 857.
Ignatios was re-elected patriarch in 867, after 10 years of living in various tortures on the island. In 1850, the island became the property of Tophane Counselor Damad Ferid Pasha, planting olive trees on the island and growing vegetables. On the death of pasha, the island was left unkempt, 1. During the World War, all the trees of the island were cut down, and the Yavuz Armor, which was passed into the hands of the allies during the invasion of Istanbul, was anchored here for a long time. The descendants of Ferid Pasha tried to make the island a settlement inhabited by elite people, for this purpose they established a housing cooperative, planted thousands of trees and built villas.