St. Patrick's disciple, St. Finian.
Ireland in St. Patrick's time had no parishes or dioceses. Our Church operated through it's monasteries, and I'd like to draw your attention to Finian, a monk who was trained in the monastery of Patrick at Armagh. Patrick's successor as abbot at Armagh sent young Finian over to a monastery in Wales to help them in their stand against the invaders.
The Welsh monastery was of importance to the Church and to civilization in that over the fifth and sixth centuries, with the Norsemen ravaging all the monasteries of Europe, the monks from all the mainland monasteries had been carrying all their scrolls of secular and sacred value to that Welsh monastery to keep them in existence.
In ten years after his leaving Ireland for Wales, Finian trained a group of monks to copy those precious scroll, and then he brought his copies to Ireland, to a place called Clonard in the county of Meath.
Traveling around Ireland by myself in 1980, I stopped at a church in the town of Nenagh where I found each of the windows dedicated to an Irish saint I had never heard of. There was Jarlath, Finbar, Colman, Ciaran.I found a plaque the identified the saints as the "Twelve Apostles of Ireland." They had been monks whom Finian had set to work copying the books of the Bible along with the literary treasures of Greek and Latin literature.
So, in honoring St. Patrick we must also honor the monks he trained to preserve the books of the Bible, and the Philosophical and Literary works of the ancient world: works that would have been lost in the Dark Ages.