St. Patrick’s Day is officially observed on March 17 each year, though celebrations may not be limited to this date. The significance of March 17 is that it’s said to be the date of St. Patrick’s death in the late 5th century (circa A.D. 493).

Saint Patrick is the patron saint and national apostle of Ireland. He is credited with successfully spreading Christianity throughout Ireland—hence the Christian celebration of his life and name.

The symbol of St. Patrick is a three-leaf shamrock, not a four-leaf clover. However, long before the shamrock became associated with St. Patrick’s Day, the four-leaf clover was regarded by ancient Celts as a charm against evil spirits.

We wear a shamrock on St. Patrick’s Day because, legend says, St. Patrick used its three leaves to explain the Holy Trinity in his teachings. (The Trinity is the Father, the Son, and the Spirit as three divine persons who are one divine being [God].)