St. Patrick was largely responsible for establishing the presence of Catholicism in Ireland. He lived from 387-493 A.D., and is renowned for building schools and converting the Irish to Catholicism. It is said that he drove the pagans out of Ireland and used the shamrock(three-leaf clover) to help people understand the trinity, which is why it is a symbol of the holiday today. Before his time, the shamrock already had a certain religious significance to the Celtic people. The druids thought that the plant had mystical powers to ward off evil spirits: to them, the three leaves were symbolic of their own deities - the "Triple Goddess." This just one example of how the Catholic church has corrupted modern Christianity: they took pagan customs, symbols, and holidays and relabeled them to represent Christian concepts. This has happened all over the world - pagan statues of a mother with a child were renamed as Mary and Jesus, and various pagan crosses were re-purposed as the cross that Jesus was nailed to. There is no precedent for this kind of religious integration in the bible:
Deuteronomy 12:30-31God specifically tells the Israelites not to worship in the same way as other religions do because God has clearly defined for them (and for us) exactly how he wants to be worshiped.
Be careful not to be ensnared by inquiring about [other nation's] gods, saying, “How do these nations serve their gods? We will do the same.” You must not worship the LORD your God in their way, because in worshiping their gods, they do all kinds of detestable things the LORD hates.
