Elizabeth, daughter of Frederick the Elector Palatine (King of Bohemia, where the Czech republic now lies) and Elizabeth Stuart (daughter of James I of England) is known mainly through her long correspondence with Descartes.

This lovely young lady was born in Heidelberg, a rather picturesque German city which I've seen personally. I'm sure it was a lovely place to grow up, and as was usual for a lot of children at the time, she spent the first few years of her life living with her grandmother, and also her aunt Elizabeth-Charlotte in Silesia.

As a child she became a member of Catholicism (odd since she's wrote to Descartes later on complaining of her brother's conversion to the faith; as well as being an abbess of a Protestant convent in later life), and as history rolled on, she refused the throne of Bohemia. A strong and smart woman, she made her own way in life.

Her interest in philosophy, and the beliefs she held also led her to avoid marriage as well. Poverty may have also played a role, as a princess her family was to give a large dowry for her, and most likely couldn't afford it. (At least she didn't go down the route of the Lydians.) In any case, after Descartes passed away in 1649 she retired to a convent in Herford in Westphalia so the chances of her marrying were significantly reduced, if not eliminated.

Her letters to Descartes are little philosophical works in themselves and the subtlety of her mind is perhaps best illustrated with a quote. She was merciless in her probing of the Cartesian inadequacy of how an immaterial substance ( like the mind ) can produce motion in the material substance (like the body). In more enlightened times she would I'm sure have been better recognize. See Cartesian Dualism.

"And I admit it would be easier for me to concede matter and extension to the soul, than the capacity of moving a body and of being moved, to an immaterial being. For, if the first occurred through 'information' the spirits that perform the movement would have to be intelligent, which you accord to nothing corporeal. And although in your metaphysical meditations you show the possibility of the second, it is, however, very difficult to comprehend that a soul, as you have described it, after having had the faculty and habit of reasoning well, can lose all of it on account of some vapors, and that, although it can subsist without the body and has nothing in common with it, is yet so ruled by it." - from a letter to Descartes in 1643.

She rose (unsurprisingly) to become the head of the convent where she stayed, and by all accounts ran it very well until her death in 1680 after a long and protracted illness.