Resarches, which are made around Sinop, show that first settlements here date back B.C. 4500 years. Name of Sinop passes as Sinuwa in Hittite documents. City, which is called Sinope in Hellen language, takes the shape of Sinop, which is used in these days. Sinop citys is a colony city, established under the name of Sinope by Miletians in B.C. 756. After city is ruled by Phyrygians, Cimmerians, Persians, Macedonians; city remains within boundaries of Pontus State in B.C. 303 and it becomes second capital city of Pontus State in B.C. 169. City, which enters under Roman rule in B.C. 67, remains under Eastern Roman (Byzantine) rule from 395 to 1213. Sinop is ruled respectively by Anatolian Seljuks Empire and Pervanoğulları, between 1214-1292 and then Candaroğulları Beylic between 1292-1461. Sinop is included into Ottoman lands in 1461. Sinop is a considerably rich city, in terms of old works. The most important opus is Sinop Castle. There are many works, belonging to Seljuks and Ottoman period. Sinop Castle is constructed during the period of Pontus King VI. Mithridates in B.C.72. The castle is composed of two sections which are citadel and bailey. While north walls of the castle protect the city from the sea, its land side is reinforced with a deep defense trench. The castle has four gates. There are epigraphs, belonging to Turk period, at north, east and south walls of the castle. While citadel serves as Sinop Jailhouse in Ottoman and Republic Periods, it is also famous to host famous journalists and authors of the period. Alaeddin Mosque is constructed by the order of Alaeddin Mosque is constructed by the order of AlaeddinKeykubat in 1214. Palace Mosque, constructed by the order of Candaroglu Calelattin Bayezit in 1374, Cezayirli Ali Pasha Mosque, belonging to Seljuks period, Seyit Bilal Tomb, Meydan Kapı Mosque, 1353 dated Fetih Baba Small Mosque, 1648 dated Mehmet Ağa Small Mosque; Süleyman Pervana Madrasah, constructed by the order of Seljuks vizier Suleyman Pervane in 1262, 1322 dated Ghazi Çelebi Tomb, 1393 dated Sultan Hatun Tomb, İsfendiyaroğulları Tomb, 1289 dated Lion Fountain, 1358 dated Ulu Bey Fountain, 1448 dated Ismail Bey Fountain, are some of the other old works, located in the city. Works, belonging to ancient bronze, archaic, classic, Hellenistic, Roman, Byzantine periods, and also ethnographic works and icons of 19th century are exhibited in Sinop Museum.