Have you ever wondered why some priests have different clothes from the other priests? For example, when you are walking pass the church, you saw a priest wearing black cassock, then you saw another wearing a white cassock. Then you saw the photo of Saint Francis or Saint Padre Pio wearing a brown cassock which is different than the photo of Saint Dominic. Or you saw a group of priests or nuns having different actions in every day life than the others that you usually see. The reason is that the Catholic Church has different religious orders. What is a religious order? Is it a different religion?