Cephalonia or Kefalonia ( or ), formerly also known as Kefallinia or Kephallenia , is the largest of the Ionian Islands in western Greece. It is also a separate regional unit of the Ionian Islands region, and the only municipality of the regional unit. It was also a former Latin Catholic bishopric Kefalonia–Zakynthos (Cefalonia–Zante) and short-lived titular see as just Kefalonia