Chasubles in polychrome silk and gold leaf with embroidery, displayed on rotation for conservation purposes. A chasuble is part of the attire used by priests for the celebration of Mass. It derives from the poenula, an ancient Roman garment mainly used by civilians’ and was often referred to as "casula" (little house) because it used to engulf the priest like a "small house". From the 15th century onwards it has been simplified to two panels of fabric, held together on the shoulders. The traditional colors are: gold and white for the main festivities and for saint’s days (not martyrs); red for celebrations related to the Passion of Christ and martyrs; green for everyday use and Sundays; violet for Advent and Lent; black for Requiem masses. Other colors – such as different shades of blue - are rarely used anymore and black hasn’t been used for over 50 years. Pink is used on the third Sunday of Advent and the fourth Sunday of Lent, the lighter shade symbolizing the imminent end of these austere times of the year.