NEPTUNE, the ‰ιau god of the sea, is probably adopted from Greek religion. The earliest reference to his worship is on the occasion when the Sibylline books included him among the gods to whom the first lectisternium was dedicated, 399 b.c. (Livy v. 13). In the poets no trait of Neptune occurs that is not directly borrowed from the Greek Poseidon. His festival, Neptunalia, was celebrated on July 23, and his temple stood near the Circus Flaminius. His worship was never popular or widespread in Rome. The god Portunus was thanked for naval victories in earlier times; but Sextus Pompey called himself son of Neptune, and Agrippa dedicated to Neptune a temple in the Campus Martius in honour of the naval victory of Actium.