Interesting things about St. Patrick
1. He lived 385–461 AD
2. He was originally born in Britain but was kidnapped by Irish raiders and was a slave in Ireland for six years. After escaping, he returned to his family and became a Deacon in the Roman Catholic Church. He returned to Ireland as a missionary.
3. Two letters, allegedly written by him, survive. He talks about visions - one when he was a slave, telling him that his ship was ready and it was time to return to his family, and another telling him to return to Ireland.
4. The 'Wearing of the Green' signifies Irish identity. This may have come from St. Patrick's evangelizing efforts by explaining the Holy Trinity by using the three leaves of a Shamrock.
5. Some legends around St. Patrick - He banished the snakes from Ireland; I remember my mother (who was Irish) telling me this story with great affect. For a long time, I thought that was the only thing he had done. Apparently, there were no snakes in post-glacial Ireland. He's also supposed to have fought with the Druids, the guardians of the indigenous religion. And the snake is supposed to have been the symbol of the Druids.
6. 17 March is believed to be his date of death, and then became the feast day.