Feast of St. Innocent I, July 28

St. Innocent I became pope in 401, succeeding Pope St. Anastasius I. It was during the rise of Pelagianism, which caused the bishops of Africa to send him a decree condemning this heresy. Innocent affirmed the decrees, prompting St. Augustine to say,

"Roma locuta, causa finitus".

Rome has spoken, the matter is ended.

Pelagianists believed that mortal sin didn't exist and that man could achieve moral perfection without the aid of divine grace.