Green is the color of the day for Tuesday, as St. Patrick’s Day celebrations take place around the world. March 17 is the day the Chicago river is dyed green and Scotland’s Edinburgh Castle is illuminated in an emerald glow. About 150 landmarks worldwide will be turned green in honor of Ireland’s patron saint, who was indeed a real person, born in the late 300s in England.

Patrick was captured by Irish invaders at age 16 and enslaved across the Irish Sea from home. After six years of slavery he returned to England, but dreamed that an Irish voice begged him to “come and walk among us once more.” After becoming a priest he returned to Ireland in his mid-40s. Patrick converted hundreds of thousands of people, confronted tyrannical kings, and established bishoprics, monasteries and convents all over Ireland before he died on March 17 in the late 400s.

Much of the common knowledge about St. Patrick is merely myth. He did not chase the snakes out of Ireland (Ireland is an island and never had snakes). No one knows whether he actually used a three-leafed shamrock to explain the Father, Son and Holy Ghost concept to early Christians. And he was sainted shortly after his death by a local bishop, not by the official saint-making practice of the Catholic Church. No miracles were performed for his sainthood.

St. Patrick was a trailblazer, which is what attracted enough attention to him that he has been given his own day, when people drink green beer, dye their hair green and pinch each other for wearing the wrong colored clothes. He never forgot his life as a slave, herding sheep on an Irish hillside, naked, cold and hungry. He was the first church father to speak against abusing women, particularly slaves. He was also the first missionary to people whom the world considered barbarians.

Author Thomas Cahill said of St. Patrick, “the step he took was in its way as bold as Columbus’ – and a thousand times more humane.”