Wikipedia
Sivriada, meaning "Sharp Island" in Turkish (, Oxeia, meaning "Sharp"); also known unofficially with the alternative folk name Hayırsızada, meaning "Useless/Unfortunate Island"; is one of the Prince Islands in the Sea of Marmara, near Istanbul.
The island, which has an area of 0.05 km², is officially a neighbourhood in the Adalar (Islands) district of Istanbul Province, Turkey.
Sivriada was often used by the Byzantine clerics as a distant place for peaceful worship, and by the Byzantine emperors as a convenient prison to detain prominent people whom they deemed troublesome. The first famous person to be imprisoned in the island by the order of emperor Nikephoros I was Plato of Sakkoudion, the uncle of renowned cleric Theodoros Stoudites, for supporting his nephew in his conflict with the emperor. Other famous people who stayed in the island for religious and political reasons were Gebon, Basil Skleros, Nikephoritzes (the chief minister of Michael VII Doukas), Patriarch John of Constantinople and Patriarch Michael II of Constantinople. The graves of those who died on the island during the Byzantine period can still be seen today.
The ruins of a Roman settlement and a 9th-century Byzantine monastery can still be seen on the shore, close to the fishermen's shelter, a small wharf which is often used by yachts. The most important buildings on the island were built in the 9th century AD, including a church, a chapel dedicated to religious martyrs, a monastery on the eastern end (with its walls still seen today) and a cistern in the center of the island (a part of which can still be seen).
In an event called the "Hayırsızada Dog Massacre" of 1910, the Mayor of Istanbul ordered (on 3 June 1910) the stray dogs in the streets to be rounded up and exiled to Sivriada. Around 80,000 dogs were transported to Sivriada and many of them died during the ordeal, mostly due to hunger and thirst on the barren island, and some due to drowning as they tried to swim towards the boats that departed. The large fire in the Aksaray neighbourhood of Istanbul on 23 July 1911, and the severe earthquake with a magnitude of 7.3 ( M) on the Richter scale that took place on 9 August 1912 (with its epicenter in the Mürefte village of Şarköy district, Tekirdağ Province) were perceived by the citizens of Istanbul as "a punishment by God for abandoning the dogs" and the practice of transporting stray dogs to Sivriada was stopped, while the surviving ones were taken back to the city. Some citizens also believed that it brought bad luck during the Italo-Turkish War (1911–1912) and the Balkan Wars (1912–1913). This is the reason why the island is known both as Sivriada (Sharp Island) and Hayırsızada (Useless/Unfortunate Island). The stray dogs of Istanbul were a popular theme in the travelogues of 19th century writers like Edmondo De Amicis and Mark Twain. In his book Costantinopoli (1878), Edmondo De Amicis (who visited the city in 1874) had envisaged the future of Istanbul as "the London of the Orient, rising upon the remnants of the most debonair city of the world"; but was pessimistic about some aspects of Istanbul's future, because he thought the city's authentic beauty, laying in its unique architecture and historic fabric, would become victim to developments in the name of civilization, such as the loss of the stray dogs.