Saint Patrick was born around the year of 385 AD, as the son of Calpurnius, a Roman tax collector. He was born in the village of Bannavem Taberniae, somewhere at the mouth of the river Severn of Wales. When Patrick was 16 years old, the land was attacked by pirates and thus he became one of the captives. He was taken to Ireland where he was sold as slave and made to work as a pig caregiver on the Slemish Mountain in the Antrim County. While he was a slave, Saint Patrick learned Irish which was very useful for him in his future mission. He led a life of solitude and prayer on the mountain for 6 years. There, he had two visions: in the first one, he was shown that he would return home and in the second vision, that his ship was ready. Thus, Patrick walked two hundreds miles across the coast, and then he managed to get on the board of the ship and get back to Great Britain, to his parents.
Later on, he went to Gaul and he studied priesthood in Auxerre, with Saint Germanus. Finally, he was consecrated as bishop and was given the mission for Ireland, following another saint which was not very successful in Ireland. Patrick had a dream in which an angel came to him holding several letters in his hands. After choosing one which wrote "The Irish Voice" he heard the Irish people calling Saint Patrick back to them.
Although St. Patrick was highly successful in spreading the Gospel in Ireland, he was not the only or the first missionary in the territory of Ireland. Thus, he got there around the year of 432 AD (yet the exact year is not known for sure). Because he had the biggest influence there in Ireland, Saint Patrick was also known as the "enlightener of Ireland".
He wrote an autobiography called "Confessions" which comprised many of his trials and disappointments encountered during his long Holy mission. Thus, Patrick once confessed to a good friend that he was troubled with a certain sin he had committed before the age of 15, and this friend of his assured him that God would have mercy on him, and support him to be consecrated as bishop. But later on, this friend betrayed Patrick by publicly exposing his teenage sin, in his attempt to prevent Patrick from actually becoming a bishop. Many years later, Saint Patrick was still crying for his friend and his sinful act of publicly betraying him.
Saint Patrick established many churches and monasteries on the territory of Ireland, but the conversion of the Irish people was by far not an easy task. The Irish were often hostile and they sometimes even attacked him, but he bravely faced any danger, insults or curses referring to his previous status of both foreigner and slave. He was even believed to have been in danger of death. Despite all the obstacles, he remained faithful to his calling and baptized many people in the name of Christ.
"Lorica" is another writing which was said to belong to Saint Patrick. In his writings, we can read about his realization of his calling, and about his decision and humbleness in fulfilling his mission. He would call himself a sinner, the most ignorant of all people, and the most despised one. He used to thank God for his victories and not rely on his own powers. He said that he owed everything to God because out of His mercy, so many people were born again unto Him.
Saint Patrick was often pictured holding a threefold shamrock in his hands, or with snakes running away from him. St. Patrick used the symbol of the shamrock in order to illustrate the doctrine of the Holy Trinity. The three leaves coming growing from the same stalk helped him explain the concept of one God in three persons.
St .Patrick died on the 17th of March 461 (some say it was in 492 AD). There are many versions regarding his last days, but most of them are legends. Some say one cannot know the place where St. Patrick was buried, whereas Saint Columba of Iona says that the Holy Ghost revealed to him that he was buried at Saul, the place of his very first church.