Summanus

In ancient Roman religion, Summanus (Latin: Summānus) was the god of nocturnal thunder, as counterposed to Jupiter, the god of diurnal (daylight) thunder. His precise nature was unclear even to Ovid.

The temple of Summanus was dedicated during the Pyrrhic War c. 278 BCE on June 20. It stood at the west of the Circus Maximus, perhaps on the slope of the Aventine. It seems the temple had been dedicated because the statue of the god which stood on the roof of the temple of Jupiter Capitolinus had been struck by a lightningbolt. Every June 20, the day before the summer solstice, round cakes called summanalia, made of flour, milk and honey and shaped as wheels, were offered to him as a token of propitiation: the wheel might be a solar symbol. Summanus also received a sacrifice of two black oxen or wethers. Dark animals were typically offered to chthonic deities.

Saint Augustine records that in earlier times Summanus had been more exalted than Jupiter, but with the construction of a temple that was more magnificent than that of Summanus, Jupiter became more honored.

Cicero recounts that the clay statue of the god which stood on the roof of the Temple of Jupiter Optimus Maximus was struck by a lightningbolt: its head was nowhere to be seen. The haruspices announced that it had been hurled into the Tiber River, where indeed it was found on the very spot indicated by them.

The temple of Summanus itself was struck by lightning in 197 BCE.

Pliny thought that he was of Etruscan origin, and one of the nine gods of thunder.Varro, however, lists Summanus among gods he considers of Sabine origin, to whom king Titus Tatius dedicated altars (arae) in consequence of a votum.Paulus Diaconus considers him a god of lightning.

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