How did René Descartes die?

It isn't quite clear how he died but we do know that he moved to Sweden in 1649.However he did not survive his first winter there.

In 1649, Queen Christina of Sweden offered Descartes to come and teach her either mathematics or philosophy in her castle. She apparently was a hard working person; Descartes was required to start his lessons with her at 5am! Descartes still maintained a life long habit he acquired in childhood to get up at 11 o'clock(he was very weak even when he was a boy, and was allowed to stay in bed for most of the morning); as he broke his habit, he broke his health too and died of pneumonia he managed to catch while on way to one of the cold early morning lessons.