You've heard of Saint Bernard dogs, Saint Elmo's Fire, and Saint Patrick's Day .... But do you know anything about the saints they're named after? Here's a crash course on who they were.

SAINT PATRICK (390-361)

The son of a Scottish deacon, Saint Patrick was captured by pirates at the age of sixteen, taken to Ireland, and forced to work as a shepherd. Six years later he returned to Scotland and became a priest. He eventually returned to Ireland, converted it to Christianity, and according to legend rid it of snakes. (He's also credited with driving the ants out of Puerto Rico, but they came back.) It was his legendary use of the shamrock to explain how the Father, the Son, and the Holy Spirit are all the one God that made the symbol synonymous with Saint Patrick's Day.

SAINT ELMO (250-300)

The inspiration for Saint Elmo's Fire, the lighteninglike static electricity that often discharges on ships at sea. Not much is known of Saint Elmo, but according to legend he was preaching a sermon one day when lightening suddenly struck the ground beside him. He amazed onlookers by continuing to preach as if nothing had happened; not long afterwards sailors began invoking his name against thunderstorms at sea. They interpreted the static electricity that discharged harmlessly on their boats as a sign that their prayers had been answered.

SAINT VINCENT DE PAUL (1581-1660)

In his lifetime Saint Vincent, a French priest, founded twenty-five charity houses, several hospitals, and cofounded the Institute of the Sisters of Charity, the first women's religious order dedicated to helping the poor and sick. He also worked with prisoners and war victims and sent missionaries all over Europe. The Society of Saint Vincent de Paul, an association of Catholic laypeople devoted to serving the poor, was founded in his honour in 1833.

SAINT ANTHONY OF PADUA (1195-1231)

Saint Anthony is the guy that generations of Catholics have prayed to for help in finding lost items. Why? According to legend, when a young friar stole a book from a monastery that Anthony had founded, he was confronted by a fearful apparition that told him to take it back. (He did.)

SAINT BERNARD (996-1081)

Bernard of Montjoux was an Italian priest who built rest houses for religious pilgrims at the tops of two mountain passes in the European Alps ... but he had nothing to do with the dogs that bear his name - his successors didn't develop the breed until centuries after his death.

SAINT JOAN OF ARC (1412-1431)

The pious daughter of a peasant farmer, Joan of Arc began having supernatural visions of Saint Michael, Saint Catherine, Saint Margaret, and other saints, at the age of 13. Her mission in life, she claimed they told her, was to save France from defeat in the Hundred Years' War, then in its eighty-ninth year, by helping the dauphin Charles of France (son of the mad King Charles VI of France) become king in his own right. After convincing him to let her lead his armies into battle - which wasn't easy, considering she was only seventeen at the time - she raised the siege of Orleans and won a major victory against the British on June 18, 1429. She attacked Paris a few months later, but failed to liberate it, and was captured in May 1430. She was burned at the stake a year later.

Note: Joan of Arc was virtually unknown before the nineteenth century and didn't become a saint until 1920. (Technically speaking, she wasn't even a citizen of France - she was born in 1412 in Domremy, which at that time was independent from France.) But Napoleon Bonaparte needed a legendary figure that he could use to inspire French nationalism, and Joan of Arc was just the woman for the job.