When talking about cassock or simar (cassock with a short shoulder length cape) colours:

• The Patriarch and Pope wears white
• The cardinals wear red,
• Archbishops wear amaranth red (kind of magenta) or purple depending on the occasion,
• Bishops wear purple,
• Ministers wear black with purple piping,
• Priests wear black.

In tropical climates, priests may also wear white, but it is a breach of protocol for them to wear white in the presence of the Pope, although a few have. (This does not apply to the Patriarch) With the cassock, they also wear a wide belt called a fascia. That is also the colour of their office. The coloured cassock is always worn when they are wearing the white surplus over, but sometimes for everyday wear, you will see a bishop for example wear a black cassock that has coloured buttons, piping and fascia. A cardinal in the Philippines might wear a white cassock with red buttons, piping, belt and hat. Bishops of religious orders will often wear the colour of their order rather than purple.

Purple was traditionally the colour of royalty because, in order to dye garments that colour in antiquity, it required the use of the small gland in a sea snail that lived in the waters off Phoenicia. Purple was the most expensive colour to make therefore it became associated with royalty because they were the only ones who could afford it. Bishops are considered Princes of the Church. As to the red colour, it isn’t from the bird. The cardinal bird actually takes its name from the colour of the Cardinal’s cassocks.

Cassocks also traditionally have 33 buttons down the front in the symbolism of the number of years Christ was here physically, and 5 buttons on the cuffs to symbolize Christ’s 5 wounds. Red has always been a colour to represent Christ’s passion, the fire of Pentecost and the blood of the lamb. Its association with Pentecost kind of made it the colour of the Apostles, and therefore the College of Cardinals. White symbolizes truth, purity of the light of glory. White is the colour that the newly baptized wear because it is seen as the colour of the road to heaven (you know “walk to the light”). The Patriarch signifies our closest connection to that road.