Saturnus is a very old, very important deity. He lends his name to not only the ancient Saturnalia festival, or to a description of character, but also to one of the planets of our solar system and a now bankrupt car company. To name a few things.
He is one of only a few deities to whom one sacrifices with their head uncovered, and not even the ancient Romans know why that was. However, he is usually depicted with his head veiled – so the sacrificing with the head uncovered might have come from the Romans not wanting to imitate him.
Several myths are ascribed to Saturnus, all revolving around his rule on the Earth:
According to one tradition, he was a mortal king who reigned over either the Capitoline hill or Latium long before Aeneas had even been born. He ruled with Ianus, another mortal (in this myth), during the great Golden Age; the Capitoline hill was, in the archaic period, called the Saturnian hill.
The other, more famous tradition comes from his association with the Greek Titan Kronos, though it diverges majorly from the Greek myth at the point when Zeus imprisons Kronos. In the Roman version, Kronos/Saturnus fled Zeus/Iuppiter and took refuge in Latium – the name Latium comes, according to the antiquarian Varro, from the Latin verb lateo, which means “to hide”.
Once in Latium, he was received by Ianus – either the mortal king or the deity – and ruled that kingdom. He introduced agriculture and “civilization” – laws and customs – to the people. His consort in the archaic tradition was Lua, and later on Ops: Lua may well be an epithet of Ops, meaning “destruction” or “unbinding”, but she was herself usually ascribed the epithet Mater (Mother) or Saturni (of Saturn).
According to the scholar John Scheid, Saturnus is the god of unbinding and loosening. We can see this from the opening ritual of the Saturnalia and the statue of Saturnus in his temple: the statue was filled with oil and it’s feet were kept bound with wool throughout the year, being loosened at the start of the Saturnalia. He was the guardian of the public treasury, which was located at his temple.
Saturnus is the god of sowing, so harvest and agriculture, (his name from satu, sowing) and of time. Along with being depicted with a covered head, he is usually shown with a sickle or key and a serpent.