St. Ambrose, at the time of his election to the episcopate, was a consular magistrate, and was not even baptized. The infula was a flock of red and white wool formed into a fillet, and worn on the head; from which ribands hung down on either side. It was a mark of religious consecration, and so worn by the priests and vestal virgins. In later times it was adopted also by the emperors and magistrates as a sign of their semi-sacred character.