Everyone knows bits of the St Patrick story so I don't want to say much. Of all that's written, my favorites are How the Irish Saved Civilization (I like all of Cahill's books) and The Celtic Way of Evangelism. I came away from having read those books realizing my faith is more Celtic than Roman based. Celtic writings are much like the Hebrew Psalms and very inclusive of the Trinity. (My favorite book for exposure to this is The Celtic Way of Prayer [I like all of DaWaal's books too].)
What's written having overflowed from Patrick (born Succat) was the Celtic based monasteries that were very inclusive of the surrounding community, focusing on relationship and embracing the common people. They loved people into The Kingdom. The Europe they evangelized to life, kinda died again, returning to the Roman cold, exclusive (exclusion) monasteries and nitty-gritty detail focus and rules.
A Palladius or Pallagious was actually the first missionary to Ireland. His name was mentioned in the newest King Arthur movie, and because I know something of him, I made the connection in the movie. He preached that people can take the 1st step to salvation without the grace of God. Augustine took steps against his followers.
St Patrick, with a satchel full of books, including Augustine's writings, like City of God and his Confessions, returned to Ireland with its un-invaded tranquility by the barbarians who were ransacking Rome and all of Europe. Thus literature was preserved until Europe was ready to take them back.
Since it's been written that Patrick used the three-leafed Shamrock to illustrate and talk about the Trinity, when I wanted to make a patchwork table centerpiece, I couldn't find a pattern for three leaves - only four leaves. So I created my own pattern, having to do more hand-stitching. I'm always changing out our table decor for the seasons and celebrations.
Another person remembered on this day in the church calendar is the man who offered his tomb for Jesus to be buried. March 17 is the Feast of Saint Joseph of Arimathea. According to a legend, Joseph was Jesus' wealthy uncle, and after his nephew's (did you ever think of Jesus as a nephew?) Resurrection and Ascension, Joseph accompanied Mary Magdalene to France. Then, alone, he made his way to Britain, bringing with him the chalice drunk from at the Last Supper, which became an ornament of the church he established at Glastonbury, Somerset. And that is how the Holy Grail ended up in England and why King Arthur was so concerned with it!
So from this legend we have so much literature - from the tales of King Arthur (and "Monty Python and the Holy Grail" movie - I'm grinning) and on to the more current The Da Vinci Code (I read that Novel and the book that followed. Good writer of a good story, but remind yourself - it's a novel). I think Dan Brown knew of this legend and extrapolated! All I'll say is, "He's an angry-at-the-church man, and doesn't know his history."
Hasn't Patrick's Breastplate prayer been put to music? Make Irish Soda Bread!