He wears all these vestments only at the celebration of the eucharist and on other very solemn occasions; at other ministrations he wears only the epitrachelion and phainolion over his cassock.
As an ecclesiastical term the word "cassock" came into use somewhat late (as a translation of the old names of subtanea, vestis talaris, toga talaris, or tunica talaris), being mentioned in canon 74 of 1604; and it is in this sense alone that it now survives.
The cassock, though part of the canonical costume of the clergy, is not a liturgical vestment.
In winter the cassock was often lined with furs varying in costliness with the rank of the wearer, and its colour also varied in the middle ages with his ecclesiastical or academic status.
In the Church of England the cassock, which with the gown is prescribed by the above-mentioned canon of 1604 as the canonical dress of the clergy, has been continuously, though not universally, worn by the clergy since the Reformation.