» For other figures with the same name as well as for the genus of flounders, see Cleisthenes (disambiguation). Cleisthenes (Greek: Κλεισθένης, also Clisthenes or Kleisthenes) was a noble Athenian of the Alcmaeonid family. He is credited with reforming the constitution of ancient Athens and setting it on a democratic footing in 508 BC or 507 BC. He was the maternal grandson of the tyrant Cleisthenes of Sicyon, as the younger… (More on Cleisthenes)