Priest cassock in Roman Catholic style

Roman Cassock is considered to a principle solemn garment. A Roman cassock often has a series of buttons down the front – sometimes thirty-three (symbolic of the years of the life of Jesus). The ordinary Roman cassock is worn by Catholic clerics (as distinct from that worn as choir dress) is black except in tropical countries, where because of the heat it is white and usually without shoulder cape (pellegrina). Colored piping and buttons are added in accordance with rank: purple for chaplains of His Holiness; amaranth red for bishops, protonotaries apostolic and Honorary Prelates; and scarlet red for cardinals.

A band cincture or sash, known also as a fascia, may be worn with the cassock. The Instruction on the dress of prelates specifies that the two ends that hang down by the side have silk fringes, abolishing the sash with tassels. A black faille fascia is worn by priests, deacons, and major seminarians, while a purple faille fascia is used by bishops, protonotaries apostolic, honorary prelates, and chaplains of His Holiness when wearing a cassock with colored trim. A black watered-silk fascia is permitted for priests attached to the papal household, a purple watered-silk fascia for bishops attached to the papal household (for example, Apostolic Nuncios), and a scarlet watered-silk fascia for cardinals. The Pope wears a white watered-silk fascia, with his coat of arms on the ends.

Pope Benedict XVI in white cassock (sometimes though unofficially called a simar) with pellegrina and fringed white fascia. 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 scarlet 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.

An elbow-length shoulder cape, open in front, is sometimes worn with the cassock, either fixed to it or detachable. It is known as a pellegrina. It is distinct from the mozzetta, which is buttoned in front and is worn over a rochet. Cassocks are sometimes worn by seminarians studying for the priesthood, by religious brothers, by laypeople when assisting with the liturgy in church, such as altar servers, and by members of choirs (frequently with cotta or, more usually in Anglican churches, surplice). http://en.wikipedia.org/wiki/Cassock