From a reader…
How come the practice is rare nowadays of bishops and monsignors wearing the mantelletta? Also, when does a bishop wear the mantelletta instead of the mozzetta? Are there specific rules for a bishop to determine if he should wear the mozzetta and mantelletta in choir?
Pope Paul VI in 1969 abolished the mantelletta for bishops. Bishops are now to wear the mozzetta. The violet mantelletta is still used by very few prelates having specific offices in the Roman Curia. There are 7 monsignors, Apostolic Protonotaries de numero (such as masters of ceremony, who witness official acts such as a Cardinal taking possession of his titular basilica, etc.), and some officials of the tribunals (such as the Defender of the Bond), and some of the canons of St. Peters Basilica. I am not sure if the canons of St. John Lateran of St. Mary Major wear the violet mantelletta or not. Some chapters have their own dress.
So, that’s why you don’t see it.
Here is Msgr. Guido Marini, Master of Ceremonies for His Holiness, in the mantelletta at the moment of the extra omnes in the last conclave.
That said… perhaps we should just revive all these things that were abolished. After all, these days law is so out-of-style. So a bishop puts on a mantelletta… who am I to judge?