Why does the priest change his clothing after the Sprinkling Rite?
During the Rite of Sprinkling, the priest is wearing the cope, which looks like an ornate cape of the same liturgical color of the day. The cope developed from ancient times when these rites before Mass would begin outside and was worn to protect the celebrant from the weather. However, now it is worn to denote the celebration of sacraments and other rites outside of the Mass. So, in the cases of Baptism and Matrimony, the celebrant ought to wear a cope and not a chasuble. Before the Mass begins but after the Sprinkling Rite, the celebrant removes his cope and puts on the chasuble (the vestment that covers the body) and maniple (the vestment worn on the arm) to show that he is beginning Mass.