The cassock is the regular garb of clergy until today. Although it’s fallen out of fashion, it’s making a little bit of a comeback.
The cassock was originally used to keep warm in drafty churches, which explains its French name
soutane, which shares the same root as the word for animal skins.
The churches were large, damp, and cold. Even if a church were to have a hearth for a fire, the place was so large that the warmth would dissipate almost immediately. As a solution, priests began wearing long coats of animal furs in the church. As time progressed, the clergy became somewhat identifiable with long coats, and when it became fashionable to wear shorter doublets, the clergy retained longer garments.
Over time, the cassock began to take shape. It was wool became more popular than skins, and it became pleated, and buttoned at the front.
The white band clerical collar was originally a band of fabric wrapped around the neck to keep the wool from chaffing the skin there.
Until recently, there were different regional variations on the cassock. Some priests in northern Europe would wear long tab “preaching bands” with it (a la St. Jean Vianney). In some places a “V” shaped notch became common at the neck, while in other a square notch became common. The “roman cassock” usually means a black cassock, with a pleat at each side, and a box pleat at the back; with thirty-three buttons in the front. The “french-cut cassock” is similar, but has a narrower skirt, and buttons on the sleeves.
Eastern styles of cassocks are very diverse, and often come in colors other than black.
And in tropical countries, the traditional cassock color was white.
One brief correction on this — White isn’t the traditional color for a cassock in tropical countries, it just allowed for comfort and practicality’s sake (by papal indult). Many clerics in tropical countries will still wear a black cassock on formal occasions.
