There's a lot on the Internet about his incredible and very interesting life. Certainly worth the read.
In Ireland, St. Patrick's day is both a holy day and a national Holiday. St. Patrick is the one who brought Christianity to the Irish. According to legend, he used a Shamrock, which has three leaves on each stem, to explain the Trinity, Father, Son and Holy Spirit. The Shamrock was sacred to the Druids, so it was very wise of him to use the Shamrock for that purpose.
St. Patrick's Day is celebrated in countries around the world.
When I was a school girl if we didn't wear green on St. Patrick's day we got pinched.
Many parades are held to celebrate the day. New York has one of the largest parades, lasting for hours with more than one hundred bands and a hundred thousand marchers.
My Irish ancestors first lived in New York after leaving their homeland. I often wonder how many of their descendants are still there, and maybe even marching in the St. Patrick's Day Parade.