In Western Christianity, Saint Mark the Evangelist, who is traditionally ascribed as the author of the Gospel of Mark in the New Testament and the founder of the Church of Alexandria, is honored on this day.
While Mark was not one of the original Apostles and he probably never knew Jesus, he is honored for the example that his life and writings established for other Christians to share the "Good News" about Jesus with others.
This day is traditionally observed as a Feast, which includes reciting the Gloria.
Here are some ways you can observe this day according to Western Christian tradition: