Gustavus Adolphus was killed at the Battle of Lützen (1632) on 16 November 1632. About this time, the English finally determined to send an expeditionary force to participate in the Thirty Years' War. Unfortunately for Frederick, it was too late. Beginning in October 1632, he had suffered from an infection that got worse in the following weeks. The famed physician Peter Spina was summoned from Darmstadt to Mainz, but nothing could be done for Frederick. Frederick died on the morning of 29 November 1632, of a "pestilential fever".