The chasuble is the outer liturgical vestment worn by the priest or bishop at Mass.  In the Greco-Roman world, the chasuble was a large cone-shaped cloth with a hole for the head worn as the outer garment.  Because it completely covered the person, it was called casula, (Latin, “little house”).  When men’s fashions changed after the Germanic invasions of the fifth and sixth centuries, the clergy retained the older style, and the chasuble became associated with clerical use.  By the ninth century the presentation of the chasuble had become part of the ordination ritual.