Hetairideia
Hetaeridia or Hetairidia (Ἑταιρίδεια) was a name of a festival among Macedonians and Magnesians (Athenaeus XIII. 572, quoting Hegesander). The origin of the Thessalian Hetaeridia is said to be related to Jason, who sacrificed to Zeus Hetaereius, "Zeus of the Companions" (the Argonauts) and called the festival by this name.