Kefalonia or Cephalonia, formerly also known as Kefallinia or Kephallenia (Κεφαλληνία), is the largest of the Ionian Islands in western Greece and the 6th largest island in Greece after Crete, Euboea, Lesbos, Rhodes and Chios. It is also a separate regional unit of the Ionian Islands region. It was a former Latin Catholic diocese Kefalonia–Zakynthos (Cefalonia–Zante) and short-lived titular see as just Kefalonia. The capital city of Cephalonia is Argostoli.