From “Costume of Prelates of the Catholic Church according to Roman Etiquette” by John Abel Nainfa:Cappa Magna8. Use
The Bishop must be vested in the cappa magna when he goes to the cathedral on feast days; and, where the cathedral is canonically constituted, having a chapter, the Bishop vested in cappa magna has a strict right to be escorted by the chapter as a body, and to have as assistants two canons. If he does not wear the cappa magna, he has no right to these honors. When vested with the mozzetta, he takes his seat in the first stall of the choirs; but when he wears the cappa magna, he sits upon his throne.
The hood of the cappa magna is used to protect the head from cold when the Prelate assists at Matins - a rare occurrence in our days - and, as a sign of mourning, when he goes to church, the last three days of Holy Week. When giving his blessing from the throne, the Bishop covers his head with his biretta, or with the hood of the cappa, as a sign of authority. Another occasion, on which the hood of the cappa is used, is when the Prelate wears a pontifical hat, as this hat is not worn directly over the head, but over the hood of the cappa magna,
In Rome, at Papal “chapels” held in the Apostolic Palace, Cardinals wear the unfolded cappa magna; Archbishops, Bishops, the Prelates di fiochetti
, Protonotaries Apostolic, The Votantes and Referees of the Signature, The Auditors of the Rota, The Clerks of the Reverend Chamber Apostolic and the Ministers of the papal chapel wear over the rochet the curtailed cappa magna. Visiting Archbishops and Bishops are however allowed to wear the mantelletta, for the reason that they usually lack the cappa required for the occasion. At such ceremonies, the Prelates di mantellone
appear in the special red cappa - crocia
- described in the preceding chapter. As Cardinals are privileged to let down the train of the cappa magna in presence of the Pope, they have a train-bearer, whose duty it is not only to carry the train of the Cardinal’s cappa, but also to hold his biretta, his breviary, papers, etc., when necessary. A Cardinal never wears his biretta in the presence of the Pope, so the train-bearer holds it all the time at Papal “chapels”. Those who wear the folded cappa at Papal “chapels” never let down its train, except on Good Friday at the adoration of the Cross; and, when these Prelates perform some liturgical function at the “chapel”, they do not wear the cappa, but put on the cotta over the rochet; Bishops, who serve the Mass of the Pope, or receive Holy Communion from his hand on Holy Thursday, observe the same rule.9. Cappa of Canons
Canons, who wear by privilege the cappa magna, are not entitled to wear the Episcopal cappa. It is understood that the cappa conceded to Canons is the folded one; and they are never allowed to let down the train, except for the adoration of the Cross on Good Friday, as was mentioned for the Prelates attending Papal “chapels”; and, as regards the occasions on which to wear the cappa, they are expected to follow faithfully the terms of the indult. The cappa, with an ermine cape, is a winter garment, as was said; therefore, Canons should not wear it in summer, but should substitute the cotta for the cappa over the rochet, unless they have received the very explicit privilege of using a summer cappa, that is the same style of cappa with a cape lined of silk instead of fur, in which case they wear the cape of fur in winter and the cape of silk in summer. Moreover, as the cappa is a choir ornament and not a liturgical garment, if a Canon has to perform ecclesiastical functions, or to administer some sacrament, he should leave aside his cappa and wear instead the cotta over the rochet.