Saaremaa or Sarema (both: säˈrĕmä) [key], Swed. Ösel, Rus. Ezel, 1,048 sq mi (2,714 sq km), island off the mainland of Estonia, in the Baltic Sea, across the mouth of the Gulf of Riga. It is irregular in shape and has a level terrain. Dairy farming, stock raising, and fishing are the chief occupations. Kuressaare is the main town and port. It is also a health resort and a popular tourist destination. The island was ruled by the Livonian Knights until 1560, when it passed to Denmark, which in turn ceded (1645) it to Sweden. Saaremaa passed to Russia in 1710 and was incorporated into newly independent Estonia in 1917. It is also called Saare.