The history was written and accepted.

The first St. Patrick's Day celebration on U.S. soil happened in Boston in 1737. The first parade? That other epicenter of Irish American immigration, New York City, 1762.

It wasn't really a big deal in Ireland until the 20th century.

Then University of South Florida history professor J. Michael Francis went to Seville, Spain, and realized Florida beat them all by more than 100 years.

There wasn't any green beer, or any beer at all most likely, but the celebration in St. Augustine did feature cannon fire.

The far-flung Spanish colony was pretty meticulous about keeping track of gunpowder. That's how Francis discovered the early party.

He was at the General Archive of the Indies scouring a 2,000 page stack of 400-year-old royal expenditures handwritten in ancient Spanish, burned around the edges from a long ago fire, when he saw an entry from 1600 saying the city used a few hundred pounds of gunpowder to celebrate St. Augustine, St. Barbara and "San Patricio."

A few entries later, March 17, 1601, was a line that read, "the people gathered and processed through the streets while the cannons from the fort fired."

"At first it didn't register, because it was so unexpected, but San Patricio, that was St. Patrick," Francis said from Washington, D.C.. "They had a St. Patrick's Day in 1600, and they even had a parade."

Francis, the Hough Family Endowed Chair of Florida Studies at USF St. Petersburg, found the story of St. Augustine's St. Patrick's celebration while doing research for La Florida: The Interactive Digital Archive of the Americas, an online archive that includes videos, interactive maps and digital reconstructions of early Florida and its diverse people.

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The royal scribe in 1601 referred to St. Patrick as the "protector of the fields," and since what was grown in the St. Augustine fields was corn, "you have this venerable Irish saint who in this Spanish military garrison becomes the patron saint of the corn," Francis said laughing.

How does that happen?

In 1597, a new governor arrived in Florida from Puerto Rico with a group of people that included a priest in his early 60s named Ricardo Arturo, or Richard Arthur, listed in documents as an "Irlandés," or an Irishman.

Arthur served as the city's parish priest from 1597 to 1604, and when he disappears from the historical record, so does St. Augustine's St. Patrick's Day celebration.

Francis said it wouldn't have been all that unusual to find Irish people living in parts of the Spanish empire. If it was after the Protestant Reformation, Irish Catholics may have even felt more secure among the Catholic Spanish, outside the British isles.

There was at least one other Irishman in St. Augustine for St. Patrick's Day 1601, a renegade named Darby Glavin (though the Spanish changed his name to David Glavid). He'd been part of England's failed Roanoke colony, and later deserted from a British ship when they stopped to get water in Puerto Rico, eventually joining the Spanish army and coming to Florida.

Though they didn't have beer, the archives show that St. Augustine did import wine from southern Spain and the Canary Islands.

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Francis said he hasn't heard from anyone in New York or Boston about his findings yet, but joked that he might need a disguise next time he goes to the Northeast. He also said it doesn't change much.

"We acknowledge these are the earliest references to St. Patrick's Day anywhere in the continental U.S., but that doesn't change the fact that Boston has such a rich Irish heritage, or that New York has been celebrating annually since 1762," he said. "In fact it fits beautifully into the broader narrative that the Irish are everywhere. Even in this small town on the frontiers of Spain's empire, you have this priest introducing Africans and Native Americans and the Spanish to St. Patrick."

Pat Smith, a spokesman for the New York City St. Patrick's Day Parade, said it's not the first time he's heard such a claim.

"From time to time, people come along and say, 'we're the first.' I say, 'fine, good luck," Smith said. "Was theirs really a parade, or was it a religious procession. We've been doing this for 257 years straight, in every kind of weather. Rain. Snow. That's pretty good. ... So yeah, we're still going to claim we're the first."