Kadıköy is a large, populous, and cosmopolitan district in the Asian side of Istanbul, Turkey on the northern shore of the Sea of Marmara, facing the historic city centre on the European side of the Bosporus. Kadıköy is also the name of the most prominent neighbourhood of the district, a residential and commercial area that, with its numerous bars, cinemas and bookshops, is the cultural centre of the Anatolian side of Istanbul. Kadıköy became a district in 1928 when it was separated from Üsküdar district. The neighbourhoods of İçerenköy, Bostancı and Suadiye were also separated from the district of Kartal in the same year and eventually joined the newly formed district of Kadıköy. Its neighbouring districts are Üsküdar to the northwest, Ataşehir to the northeast, Maltepe to the southeast, and Kartal beyond Maltepe. The population of Kadıköy district, according to the 2007 census, is 509,282.
Kadıköy is an older settlement than most of those on the Anatolian side of the city of İstanbul. Relics dating to 5500-3500 BC (Chalcolithic period) have been found at the Fikirtepe Mound, and articles of stone, bone, ceramic, jewelry and bronze show that there has been a continuous settlement since prehistoric times. A port settlement dating from the Phoenicians has also been discovered. Chalcedon was the first settlement that the Greeks from Megara established on the Bosphorus, in 685 BC, a few years before they established Byzantium on the other side of the strait in 667 BC. Chalcedon became known as the 'city of the blind', the story being that Byzantium was founded following a prophecy that a great capital would be built 'opposite the city of the blind' (meaning that the people of Chalcedon must have been blind not to see the obvious value of the peninsula on the Golden Horn as a natural defensive harbour). The fourth ecumenical church council, Council of Chalcedon, was held there in 451 AD.
Chalcedon changed hands time and time again, as Persians, Bithynians, Romans, Byzantines, Arabs, Crusaders, and Turks passed through the area, which was badly damaged during the Fourth Crusade and came into Ottoman hands in 1353, a full century before Constantinople. Thus, Kadıköy has the oldest mosque in İstanbul, built almost a century before the conquest of Constantinople in 1453.
At the time of the conquest, Chalcedon was a rural settlement outside the protection of the city. It was soon put under the jurisdiction of the Constantinople courts, hence the name Kadıköy, which means Village of the Judge. In the Ottoman period, Kadıköy became a popular market for agricultural goods and in time developed into a residential area for people who would commute to the city by boat.
According to Ottoman estimations of 1882, the district of Kadıköy had a total population of 6,733, consisting of 2,695 Muslims, 1,831 Armenians, 1,822 Greeks, 249 Jews, 92 Latins, 28 Bulgarians and 16 Catholics.
More detail on the Wikipedia webpage (link below) can be found under the headings: 2 Modern life, 3 Surrounding residential areas, 4 Architecture, 5 Sport, 6 Religion, 7 International relations, 8 See also, 9 References and 10 External links.