Corfu (Greek: Κέρκυρα, Kérkyra, [ˈcercira]; Ancient Greek: Κέρκυρα or Κόρκυρα; Latin: Corcyra; Italian: Corfù) is a Greek island in the Ionian Sea. It is the second largest of the Ionian Islands. Its north-eastern coastline lies off the coast of Sarandë, Albania, from which it is separated by straits varying in breadth from 3 to 23 km (2 to 15 mi), including one near ancient Butrint, while the south-east side of the island lies off the coast of Thesprotia, Greece. The island is part of the Corfu Prefecture and includes twelve of the sixteen municipalities or communes in the prefecture and communities of Ereikoussa, Mathraki, Othonoi, and Municipality of Paxoi, which are all separate islands.
The principal town (pop. 28,185) of the island is also named Corfu, or Kérkyra in Greek, as is its municipality (pop. 39,487). Corfu is home to the Ionian University.
The island is connected to the history of Greece from the beginning of Greek mythology. Its Greek name, Kerkyra or Korkyra, is related to two powerful water symbols: Poseidon, god of the sea, and Asopos, an important Greek mainland river. According to myth, Poseidon fell in love with the beautiful nymph Korkyra, daughter of Asopus and river nymph Metope, and abducted her. Poseidon brought Korkyra to the hitherto unnamed island and, in marital bliss, offered her name to the place: Korkyra, which gradually evolved to Kerkyra (Doric). Together, they had a child they called Phaiax, after whom the inhabitants of the island were named: Phaiakes. This term was transliterated via Latin to Phaeacians.
The island's history is laden with battles and conquests. The legacy of these struggles is visible in the form of castles punctuating strategic locations across the island. Two of these castles enclose its capital, which is the only city in Greece to be surrounded in such a way. As a result, Corfu's capital has been officially declared a Kastropolis ("castle city") by the Greek government. Corfu was long controlled by Venice, which repulsed several Turkish sieges, before falling under British rule following the Napoleonic Wars. Corfu was eventually ceded by the British Empire along with the remaining islands of the United States of the Ionian Islands, and unification with modern Greece was concluded in 1864 under the Treaty of London.
In 2007, the city's old town was designated for the UNESCO World Heritage List, following a recommendation by ICOMOS.