Saturn a major god at his time was the son of noble Coelus and Terra. He was married to his sister Vesta. Vesta and her sisters told their mother to join them in their plot to exclude their older brother (Titan) from his birthright and to raise their fathers throne.
They tried everything they could and finally they succeeded and Titan was obliged to resign his claim although he did have a condition and that condition was that Saturn could not have any male children. It was said that Saturn observed this covenant so faithfully that he devoured them as soon as they were born.
However Vesta delivered twins Jupiter and Juno. Saturn was named Saturn because he was always so happy and mild that they thought that would be a perfect name for him. His name means golden age. Saturday was named after Saturn a true god.