Sisinnius (* in Syria; † February 4 708) was probably chosen to January 15, 708 around the Pope and died just three weeks later, a serious illness.
Sisinnius was probably born in Syria, the son of John; be more exact birthplace is unknown.
Little is known of him, he was Enthroned after a Sedisvakanz of 89 days on January 18, 708 He was, it is said, so seriously ill that he could not even feed himself. Nevertheless Sisinnius to have tried to exercise his papal office as well as possible. About his actual official acts is only known that he gave orders to prepare limestone for the repair of the walls of Rome, and that he blessed a Corsican bishop shortly before his death. He was buried in St. Peter's Basilica.