DELIA. An ancient quadrennial festival of the Ionians, held on Delos (hence the name ; the local title was Apollonia, which seems to have been always used for the corresponding yearly festival) . It was in honour of Apollo; after great brilliancy in early times, it declined as the political importance of Ionia did so, but was revived in 426 by the Athenians as part of their im perial policy.
See "Homer" Hymn, iii., 146 ff.; Thucydides, iii. Io4 ; and M. P. Nilsson, Griechische Feste (Iqo6), p. 144 if.