trittys

thumb|Horos (boundary stone) of the trittyes of Pedion and Thria (both tribe of Oineis), in [[Piraeus, mid-5th century BC.]]

thumb|Map of ancient Attica divided into its thirty trittyes. Those belonging to the same [[phyle are numbered and coloured accordingly.]] The trittyes (; trittúes), singular trittys (; τριττύς trittús) were part of the organizational structure that divided the population in ancient Attica, and is commonly thought to have been established by the reforms of Cleisthenes in 508 BC. The name trittys means "third", and is named such because there were three types of regions in each trittys. There were thirty trittyes and ten tribes (before Cleisthenes, there were only four tribes organized by royal families) named after local heroes in Attica. Trittyes were composed of one or more demes; demes were the basic unit of division in Attica, which were the smaller units of population that made up the trittyes. (see here - - for a very descriptive map of the demes and tribes).