Saint Patrick was a 5th-century Christian missionary to Ireland. St Patrick is connected to many of the festivals and much of the history of Ireland, and to people all over the world who have Irish ancestors. St Patrick's Day is celebrated in many parts of the world. It is the day he is believed to have died: March 17th. But St. Patrick was not Irish. He was English. He was a Romano Britain, an English person who grew up and live in the last days of a land that had been occupied by Romans for four centuries.
So, to understand St Patrick, one of the first missionaries in Ireland, you have to go back fifteen hundred years to a Britain on the very edge of the Roman Empire. It was a land so remote and difficult to control that emperor Hadrian had built a great wall from coast to cost just to control the Picts – the Barbarians – of the north. It was also a land just a couple of days sail from another land, which the Romans knew as Hibernia and which we call Ireland. It was a land beyond the reach of the Romans, and they never conquered it. (more in the book below)