What the Heck Happened to St. Patrick's Day?

In case you don't know the story (I didn't) - here it is, from a GodSpeaks devotional:

St. Patrick's Day was originally a special day that honored a man through whom the Lord did an incredible work. Around the year 390, Patrick was born into a Christian family in Britain. At age 16, his village was raided by the Celts and he was captured and taken to Ireland where he was sold as a slave to one of the tribal chiefs. He eventually escaped from his captors and returned to Britain. Years later, Patrick had a dream in which he saw Irish children begging him to bring the gospel to them. He took this as a sign of God's calling, and, in 432, he returned as an ambassador of Christ to the very land from which he had once escaped.

Little is known about what happened next, but, just a few years later, most of Ireland had converted to Christianity. Close to 300 churches were established and roughly 120,000 people had been baptized as Christians. This work had an ongoing impact as Ireland became the major center for the translation and preservation of Scripture. There's no telling how many souls were eternally affected as a result of the work that God did through Patrick. Consequently, the church in Ireland decided to set aside the day of his birth, March 17, by tradition, in honor of his service for the kingdom.