Innocent I — son of Pope Anastasius I (an unusual papal lineage) — became pope in 401 and reigned through the Visigothic invasion of Italy. He was absent on diplomatic mission at Ravenna when Alaric sacked Rome on August 24, 410 — the first time the eternal city had fallen to a foreign enemy in eight hundred years.
He was an energetic defender of papal authority. He insisted that all important questions raised by other bishops be referred to Rome and that the major liturgical, disciplinary, and ecclesiastical traditions of Rome were normative for the universal Church. His letters to African bishops on the Pelagian controversy — which condemned the teaching of Pelagius and confirmed the African councils that had judged it — closed the debate; Augustine famously said 'Rome has spoken; the case is closed' (in fact a paraphrase of Innocent's words).
His pontificate is the high water mark of the late ancient papacy. He is named in the Roman Canon of the Mass among the popes commemorated at every Eucharist.