Who was Iphigenia? What did Cincinnatus do? A thousand gods, heroes and tyrants of the classical world, each explained in the time it takes to read a text message.
A derivative form from summus, the highest, an ancient Roman or Etruscan divinity, who was of equal or even of higher rank than Jupiter. As Jupiter was the god of heaven in the bright day, so Summanus was the god of the nocturnal heaven, and hurled his thunderbolts during the night.