St Patrick's Day is celebrated annually on March 17.  This year, it falls on a Thursday. The celebration started out as a religious feast day in the ninth or tenth century to honor the patron saint of Ireland. Here's everything you want to know about  St Patrick's Day History and Traditions.

St Patrick was born during the fourth century. Most people thought the saint is Irish, but his exact birthplace is still unknown.  Historians say his birthplace is most likely in Wales, England or Scotland.

In his teenage years, he was enslaved by pirates and brought to Ireland, where he worked as a herdsman.  After hearing the voice of God, he managed to escape from his captors. Years later, the voice urged him to go back to Britain as a missionary and preach Christianity.

He spent more than 30 years of his life in establishing churches, schools, and monasteries across the country. Interestingly, he used clovers to explain the Holy Trinity and convert pagan Druids. Patrick was later appointed as successor of the first bishop of Ireland.

Irish Catholics honor the saint on the anniversary of his death. They also venerate him through praying for missionaries.

So now, why do people wear green on St Patrick's Day? Irish tradition says green is the color of the Catholics and orange is the color of the Protestants. By looking at the Irish flags, the colors are separated by white that symbolizes peace. Furthermore, people started to wear green ribbons and shamrocks during the 17th century.  Irish legend also says people who wear green are invisible to leprechauns - a bearded man who pitches any person that they could see.

Additionally, Irish soldiers wore green uniforms on March 17 as a form of political statement during the Irish Rebellion of 1798.

Drinking is also part of St. Patrick's Day. The phrase "Drowning the Shamrock" comes from the tradition of floating the shamrock in a whiskey before drinking it. According to Telegraph, popular Irish toasts during the celebration are "may the roof above us never fall in" and "may we friends beneath it never fall out."

People also believe drinking during St. Patrick's Day can bring good luck.

Many countries around the world commemorate the Irish cultural pride holiday. However, St. Patrick's Day is an official holiday only in the Canadian province of Newfoundland and Labrador, the Caribbean island nation and Ireland.