St Ambrose (339-397CE) was a fourth century bishop of the early church.
He originally trained in law and was serving as Roman Governor in Aemilia-Liguria in Milan when he was unexpectedly elected Bishop of Milan in 374CE by the people of the City. At the time he was a Catechumen receiving instruction in the Christian Faith before being Baptised.
He died in 397CE while still in office - he was not martyred.