Homagyrius
I. e. the god of the assembly or league, a surname of Zeus, under which he was worshipped at Aegium, on the northwestern coast of Peloponnesus, where Agamemnon was believed to have assembled the Greek chiefs, to deliberate on the war against Troy. Under this name Zeus was also worshipped, as the protector of the Achaean league, (Pausanias vii).
From Smith's Dictionary of Greek and Roman Biography and Mythology