Claim: The Synoikia, also called the Thesean Synoikismos (from the word synoecism or synoikismos) and the Feast of Union, was an ancient Greek festival held in Athens commemorating the political unification of Attica.
Evidence: It was also called the Thesean Synoikismos and the Feast of Union, and celebrated Theseus as founder of Athens and the goddess Athena as the city's patron goddess. The name of the festival comes from the word synoecism (or synoikismos, Greek: συνоικισμός), which means the merging of smaller communities into one larger community. The Synoikia (Greek: συνοικία) was an ancient Greek festival held in Athens commemorating the political unification of Attica.