St. Patrick was born in England to wealthy parents around the end of the fourth century. Kidnapped by Irish pirates at the age of 15, he was sold into slavery in Ireland where he spent six years in captivity. After escaping, he eventually became a missionary in Ireland.
St. Patrick was 20 years old when he escaped captivity by fleeing to the coast. There, he found sailors who helped him return to England where he reunited with his family.
It was after his escape that he wrote a letter telling of an angel speaking to him in a dream. The angel, he wrote, told him to become a missionary in Ireland. Patrick attended training to become a priest and was eventually made a bishop. He returned to Ireland in March of the year 433. For over 40 years, Patrick preached and converted people throughout Ireland. He died March 17, 461, after years of suffering and living in poverty. Many villagers in Ireland mourned Patrick's death on that day each year. The annual mourning slowly evolved into a celebration.
While current St. Patrick's Day celebrations use green as the primary color, the patron saint's color was actually blue. The use of green was adapted from Ireland's association with green hills and the shamrock, which St. Patrick used to explain the Holy Trinity to his followers.