Roman Catholic and more traditional Protestant clergy wear green vestments at liturgical celebrations during Ordinary Time. In the Eastern Catholic Church, green is the color of Pentecost. Green is one of the Christmas colors as well, possibly dating back to pre-Christian times, when evergreens were worshiped for their ability to maintain their color through the winter season. Romans used green holly and evergreen as decorations for their winter solstice celebration called Saturnalia, which eventually evolved into a Christmas celebration. In Ireland and Scotland especially, green is used to represent Catholics, while orange is used to represent Protestantism. This is shown on the national flag of Ireland.