The casula was a versatile outer garment worn in Rome from about 200 B.C.E. and, in modified forms, is still in use throughout the world today. The casula, which means "little house," was a large rectangular or oval piece of fabric, usually made of wool, into the center of which was cut a hole for the head. This poncho-like garment slipped over the head and protected the user from bad weather, what some may consider an early version of the raincoat. It was often made of a dark color and extended to about the knee.
The casula was actually an adaptation of an older garment, called a paenula. The paenula was a casula with a pointed hood. The casula was itself adopted for use in the Roman Catholic Church as one of the vestments, or ceremonial robes, of the priest. Roman Catholics refer to the garment as the chasuble. Chasubles used by Roman Catholic priests can be very ornate, with colorful patterns and rich embroidery. They are still used to this day.
Bigelow, Marybelle S. Fashion in History: Apparel in the Western World. Minneapolis, MN: Burgess Publishing, 1970.
Payne, Blanche, Geitel Winakor, and Jane Farrell-Beck. The History of Costume. 2nd ed. New York: HarperCollins, 1992.