Pandionis (Ancient Greek: Πανδιονίς) was an ancient phyle (tribe or clan) of Attica. It was one of the original ten tribes in which Athenian citizens were divided after the late 6th century BC reforms of Cleisthenes.[1] The citizens of Pandionis were known as Pandionidae (Ancient Greek: Πανδιονίδαι).[2] At the time of its creation, Pandionis was composed of eleven demes, although the number of demes changed in the following centuries.[3] The tribe was named after the eponymous hero Pandion, usually thought to have been either Pandion I or Pandion II, two of the legendary Kings of Athens.