Ambrose of Milan

Lived

c. 339–397

Era

The fathers

Where

Milan

Tradition

The apostolic communities

A bishop who made an emperor do penance

The Roman governor of Milan, acclaimed bishop by the crowd while trying to keep order at a disputed election, and baptised, ordained and consecrated inside a week.

Why it matters

He barred Theodosius from communion until he did public penance for the massacre of thousands at Thessalonica, and the emperor complied — the first time the church successfully disciplined an emperor, and a precedent the west built on for a thousand years. He introduced congregational hymn-singing to the west, partly as a way of holding a congregation through a siege of his basilica. And he preached the sermons that dismantled Augustine's objections to Christianity, then baptised him.

All the figures, from the apostolic age to the present, or the timeline they stand in.