PENSACOLA, Fla. -- Amateur archaeologist Tom Garner had time to kill and took a drive along the Florida Panhandle. Seeing a newly cleared lot, he poked about, hoping to find artifacts from the city's rich history dating back centuries to the Spanish explorers.

Garner stumbled upon some shards of 16th century Spanish pottery. The discovery has made him a celebrity in archaeological circles.

Experts have confirmed the find as the site of the long-lost settlement of a doomed 1559 Spanish expedition led by Tristan de Luna. The discovery bolsters Pensacola's claim as the first European settlement in the modern-day United States, six years before the Spanish reached St. Augustine on Florida's Atlantic seaboard.

The expedition was scuttled by a hurricane in September 1559, shortly after the fleet arrived in Pensacola. Five ships sank.

Archaeologists diving in Pensacola Bay found part of Luna's doomed fleet in the 1990s, including the anchor of one ship. But the exact site where Luna and 1,500 soldiers, Mexican Indians and Spanish settlers lived for about two years had eluded searchers until now.

Many believed Luna's settlement had washed away in storms or was entombed beneath centuries of development.

Archaeologists from the University of West Florida are now digging in the quaint, waterfront neighbourhood.

"This gives us a whole new window on early Spanish colonialism here in the United States," said John Worth, an associate professor of anthropology with the University of West Florida.

Luna's mandate from the Spanish king was to construct a village that would include a church, government house, town plaza and residential site. The archaeologists hope to find out how far the work progressed.

Had Luna succeeded in colonizing the northern Gulf Coast, it would have changed the history of North America, Worth said. A lasting Spanish foothold in the Panhandle could have checked later French influence on the region, he said.

Spaniard Pedro Menendez founded the first successful Spanish settlement at St. Augustine in 1565.

Cal Halbirt, city archaeologist for St. Augustine, said the discovery should add new understanding to Florida's colonial past. Meanwhile, St. Augustine proudly maintains its claim as the oldest continuously occupied European settlement city in the present-day U.S.