I will not elaborate too long on this, to minimize the impact on your short attention-spans, but jump to the important parts of his story, to his impact on history thereafter, and hasty conclusions.
He was originally a Welshman called Maewyn Succat and first came to Ireland after having been enslaved by Irish raiders, in the latter part of the 5th century. Working there guarding sheep (a profession sadly lost in these modern times, to the dismay of predator conservationists), he eventually escaped and returned to Wales, years of praying thereafter resulting in visions of a man coming from Ireland, bringing letters bearing "The Voice of the Irish".
This collective voice beckoned for his return, and he finally saw Irish shores again, working as a missionary, bringing forth from Providence the Holiest of Beverages, Beer.
He created the first ever pub, and had an untraditional way of baptising new believers by drenching them in beer. He never charged for any of the beer, and he never accepted donations.
The Irish mob, seeing the potential for profit with the Holy Beverage, saw to it that Patrick was tried for his heresy by disenchanted noblemen for economic disreptancy, and by means of the trial, secured ownership of his places of worship, the Pubs.
But the Irish people, now having to pay for what they had earlier accquired freely during Patrick's sermons, never forgot the pioneering he had contributed in making them all jolly green alcoholics.
Nowadays, March 17th is both the holiday of St. Patrick, and the international day of "No excuse not to have a beer today".
The Germans, of course, not wanting to be outclassed by some islanders in being champions of drunkenness, with their own type of beer having originated in the province of Bohemia (modern-day Czech republic), decided to dedicate an entire month (October, hence Oktoberfest) to the celebration of beer, and legislated the proper manufacture of beer in the Reinheitsgebot (the beer purity law) of 1516.
Unfortunately, this prolonged drunkenness led to, in an unfortunate turn of events, that a young artist from Austria named Adolf misinterpreted the whole thing and thought the Reinheitsgebot was about races. The results are common history.
For that reason, people have been cautious about this, and the consequences thereof is that most have no problem drinking on March 17th, but feel politically incorrect in being drunk throughout October.
The Reinheitsgebot was finally invalidated in 1987, Germany wanting to avoid misunderstandings of "purity" once more letting somebody find a legal precedence for eugenics, and cause the nation total embarassment yet again.
