Palaeopolis, Corfu in the context of "Corfu"

Corfu (/kɔːrˈf(j)uː/ kor-FOO, -⁠FEW, US also /ˈkɔːrf(j)uː/ KOR-foo, -⁠few) or Kerkyra (Greek: Κέρκυρα, romanized: Kérkyra, pronounced [ˈcercira] ) is one of the Ionian Islands in western Greece, and is separated by the Straits of Corfu from the mainland of Greece and Albania. It is the northernmost island on Greece's west coast except for its satellite Diapontian Islands, which are also the westernmost point of all Greece. Corfu and the Diapontian Islands mark the International Hydrographic Organization border between the Ionian Sea to the south and the Adriatic Sea to the north. Within the Ionian Islands region, the regional unit of Corfu extends as far south as the Paxoi. The capital and largest city of the regional unit is also named Corfu.

The island is bound up with the history of Greece from the beginnings of Greek mythology, and is marked by numerous battles and conquests. Ancient Korkyra took part in the Battle of Sybota which was a catalyst for the Peloponnesian War, and, according to Thucydides, the largest naval battle between Greek city states until that time. Thucydides also reports that Korkyra was one of the three great naval powers of Greece in the fifth century BCE, along with Athens and Corinth. Ruins of ancient Greek temples and other archaeological sites of the ancient city of Korkyra are located in Palaiopolis. Medieval castles punctuating strategic locations across the island are a legacy of struggles in the Middle Ages against invasions by pirates and the Ottomans. 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.