middle of the century, Anglican clergy began turning the collar around backward, creating the first versions of the "dog collar". This form of distinctive dress was seen as a controversial affectation of the high church party, but as time progressed the collar-turned-backward became more common and even survived the demise of detachable collars among the general public. Although the black waistcoat has given way to a black shirt, the collar has become a daily part of a clerical costume for most Anglican clergy. However, some Anglican clergy join with ministers of reformed churches in eschewing distinctive clerical costumes entirely.. During the 20th century, Anglican bishops began wearing purple (officially violet) shirts as a sign of their office. Along with the pectoral cross and episcopal ring, this marks them off from other clergy in appearance. While there is no law among the churches of the Anglican Communion that prevents other members of the clergy from wearing a purple shirt, to do so is generally not considered appropriate. Until the Regency period, Anglican clergy regularly wore the cassock in public. After enjoying something of a revival in the mid-20th century, this custom is again less common. The traditional Anglican headwear with the cassock was the Canterbury cap, which is now seldom used. Many Anglo-Catholic clergy still wear the biretta. From the mid-18th century, bishops and archdeacons traditionally wore a shortened version of the cassock, called an apron (which hung just above the knee), along with breeches and gaiters. The gaiters, buttoned up the side, would cover the trouser leg to a point just below the knee. This form of everyday vesture, common up until the 1960s, is now almost extinct. (This was appropriate for them in the time when some of their travelling would be on horseback but continued into the middle of the 20th century.) Some Anglican clergy favour a double-breasted cassock (known as a Sarum cassock), often with an external button at chest level on which to hook an academic hood (which is worn as part of the choir habit). However, many clergy, especially most Anglo-Catholic clergy, choose the single breasted cassock. Like Roman Catholic clergy, some Anglican clergy wear the fascia (known within Anglicanism as a cincture) around the waist, while others prefer a belt. Where extra protection from the elements is needed a cloak may be worn over the cassock. Clergy of the Royal Peculiars, senior chaplains to