With the establishment of the Republic of Turkey in 1923, the island became a property of the Turkish state, and in 1947 Yassıada was handed over to the Turkish Navy which built several school buildings. Between 1960 and 1961, these school buildings became the venue for the trials of the members of the former ruling party, Democrat Party, after the military coup of 1960. Several of the defendants were sentenced to death, and three of these, including the former Prime Minister Adnan Menderes, were taken to İmralı Island (further southwest, near the southern shoreline of the Sea of Marmara) and executed there in 1961.