In the West, the cassock is little used today except for religious services; but in many countries it was the normal everyday wear of the clergy until the second half of the 20th century, when it was replaced even in those countries by a conventional suit, distinguished from lay dress by being generally black and by incorporating a clerical collar.
The ordinary Roman cassock worn by Catholic clerics is black except in tropical countries, where it is white. Coloured piping and buttons are added to the specific cassock: purple for that of chaplains of His Holiness; amaranth red for that of bishops, protonotaries apostolic and Honorary Prelates; and scarlet red for that of cardinals.
In choir dress, chaplains of His Holiness wear their purple-trimmed black cassocks with a cotta, but bishops, protonotaries apostolic, and honorary prelates use (with a cotta or, in the case of bishops, a rochet and mozzetta) cassocks that are fully purple (this purple corresponds more closely with a Roman purple and is approximated as fuchsia) with amaranth trim, while those of cardinals are fully scarlet with scarlet trim. Cardinals have the additional distinction of having both choir cassock sleeves and the fascia made of scarlet watered-silk . The cut of the choir cassock is still a Roman-cut or French-cut Roman cassock.
In the past, the cardinal's entire choir cassock was made of scarlet silk moiré along with a train as well (some twenty-six inches which was later abolished by Pauline Motu Proprio in 1969)..
The general rule of the Roman Catholic Church is that the elbow-length shoulder cape, open at the front, worn with the cassock is permitted only for bishops and cardinals. But at the time of the restoration of the hierarchy in