Pope Severinus

Pope Severinus (died 2 August 640) was the bishop of Rome elected in October 638. He was caught up in a power struggle with Byzantine Emperor Heraclius, who pressured him to accept Monothelitism. Severinus refused, which for over eighteen months hindered his efforts to obtain imperial recognition of his election. His pontificate was finally sanctioned on 28 May 640, but he died two months later.

Source: Wikipedia — https://en.wikipedia.org/wiki/Pope_Severinus