Chlemoutsi (Greek: Χλεμούτσι or Χλουμούτσι) is a medieval castle in the northwest of the Elis regional unit in the Peloponnese peninsula of southern Greece, in the Kastro-Kyllini municipality.It was built in the early 1220s by the Crusader rulers of the Principality of Achaea as their main stronghold, and is perhaps the finest fortification of the early period of Frankish rule in Greece preserved in the country today.