Mnemosyne is the Titanide personification of memory. She is a daughter of Uranus and Gaia and is considered to be the first Muse in Greek mythology. Muses were women that inspired greatness in the ones that they picked as lovers. Zeus is the one that felt inspired first and then fathered the other muses on her. Each of the muses has its own domain, be it music, rethorics, history or astronomy.
The eloquence with which poets and Kings speak to their audience is said to be inspired by Mnemosyne’s daughters. In Hades, the Titanide rules over a pool that is filled with water that returns memories to those that have lost them.