In Western iconography, he is depicted in bishop's attire.

An excerpt from the article 39 facts about Ireland

Typically, his attribute is a shamrock held in his hand - a white clover leaf (a symbol of Ireland) derived from the ancient Celtic triskelion (a sign composed of three identical elements).

As legend has it, Saint Patrick was to use the three-leaf clover to explain the dogma of the Holy Trinity during his evangelizing mission in Ireland.

The Catholic Church remembers Saint Patrick's Day on March 17.