Saint Patrick is not. He was never officially canonised by the Papacy and was declared a saint by the Irish. Which is how it was done in the 5th century but still, he's not official. He's a people's saint.

In the middle of the 5th century Saint Patrick a 16 year old, Romano-Welsh, son of local officials, was kidnapped off a Welsh beach by Irish raiders. He was enslaved by Niall of the Nine Hostages, and served as a goatherd up a rocky mountain for six years, where the winter California just had would be considered a vast improvement. He escaped, which was a particularly brave or insane attempt as he would have been executed had he been caught. Returns to Wales, becomes a priest, goes to Rome and gets permission to convert Ireland and heads back. The absolute nutter.

Recently a Roman trading fort in Ireland was found at Drumanagh. This was likely Patrick's first point of landfall, according to history Patrick was told to move on from his first landfall, he heads further north and makes landfall on an island off the coast of Skerries that is today named St. Patrick's island. A couple of miles north of Drumanagh and easily visible from there. The locals soon ate his goat so don't go calling Skerries people "goat eaters" unless you want a fight.

Things worked out for Patrick, he wasn't promptly killed by any of the leaders he tried to convert. Over the next 50 years Ireland is converted to Christianity, but also Christianity is converted to paganism - the Celtic cross incorporates the pagan element of the sun, all of the major Celtic festivals are translated into Christianity through the transformation of pagan deities into saints.

At the same time Patrick is converting Ireland, the Romans depart Britain. Arthur and the last of the Romano-British fight a rearguard action against the natives and invasions of the Saxons. A fight that is lost within a few decades of the death of Patrick.

Monastic Christianity took strong root in Ireland and became a centre of learning celebrated throughout Europe. Latin was new to the Irish and the run on words confused them. To make comprehension easier they began putting spaces between the latin words. When Irish monks converted Charlemagne the spaces came with them.