Themis was an early bride of Zeus and his first counsellor. She was often represented seated beside his throne advising him on the precepts of divine law and the rules of fate.
Themis was closely identified with Demeter Thesmophoros ("Bringer of Law"). Indeed Themis' six children, the spring-time Horai and death-bringing Moirai, reflect the dual-functions of Demeter's own daughter Persephone. Themis was also identified with Gaia (Earth) especially in the role of the oracular voice of earth.
Zeus and Themis would become close and it was said that Themis would become the second wife of Zeus, after Zeus had swallowed Metis his first wife. The union of Themis and Zeus was said to have brought forth two sets of children, the three Horai and the three Moirai.
In Greek mythology the first generation of Horai were three sisters named Dike, Eirene, and Eunomia. The Horai were primarily goddesses of the season, but were also closely associated with the division of time, and thus in both roles were considered to be goddesses of order, just like their mother.
The Moirai are also often referred to as the Fates, and they like the Horai were three sisters, Atropos, Clotho and Lachesis. The Moirai were in control of the life thread of all mortals, and even gods were guided by them.
The relationship of Themis and Zeus would eventually come to an end, for famously, later on Hera would become wife of Zeus. The fate of Themis though was nothing like Metis, and even after Zeus and Themis were separated, Themis remained a revered goddess, with Themis offering guidance to her former husband, and even plotting with Zeus.
In some versions of the tale of the Trojan War, it was Zeus and Themis who planned the whole war to bring an end to the Age of Heroes, a plan that started with Eris throwing the Golden Apple, to the Sacking of Troy.
Themis is also said to had helped Leto, along with her sisters Theia and Rhea, with a birth of Apollo and later suckled him with heavenly nectar and ambrosia. According to Ovid`s Metamorphoses, Themis was the one who released Sphinx to Thebes to annoy travellers with its riddles. And once Oedipus solved the riddle and destroyed Sphinx, Themis was heartbroken and angered. Without delay she sent another savage beast, this time to ravage the city.