A ferraiolo is a long cape worn by Catholic clergy on formal, non-liturgical occasions such as graduations. Before 1969, the ferraiolo was required attire for clergy admitted to the presence of the pope. The color of a ferraiolo is determined by the rank of the cleric: black for priests, purple for bishops, and red for cardinals. Before 1969, members of religious orders could alternately use a ferraiolo that matched the color of their habit.

Sources:

“Ferraiolo,” Wikipedia, April 8, 2024. https://en.wikipedia.org/wiki/Ferraiolo.

Lo Bello, Anthony. The Origins of Catholic Words: A Discursive Dictionary. Catholic University of America Press, 2020. https://doi.org/10.2307/j.ctvx077ht.5.