James Monroe had pretty modest digs for a U.S. president—or so scholars thought. From 1799 to 1823, the nation's fifth leader lived near Charlottesville, Virginia, on a plantation known as Highland. There, experts believed that Monroe resided with his family in a humble two-story house—a far cry from neighbor Thomas Jefferson's palatial Monticello estate. Years later, a surviving portion of the structure was preserved as the president's historic home.

Turns out, historians got a lot wrong about Highland—and Monroe. Archaeologists recently uncovered the foundations of another house on the plantation’s grounds, The Washington Post reports. It’s more than twice the size of the cottage, and was likely once as grand as Monticello. This mansion was Monroe’s main estate; the rustic cottage was actually his guesthouse.

“We have made a stunning discovery. These exceptionally well-preserved remains are just beneath the ground surface in the front yard of the 1870s wing attached to the standing Monroe-era house,” Sara Bon-Harper, executive director of James Monroe’s Highland, said in a release. “This finding represents a breakthrough in how the nation understands Monroe and how he lived.”

Highland is today owned by the College of William & Mary, Monroe’s alma mater. Archaeologists have been examining the plantation’s grounds for the past two years; in the spring of 2015, they uncovered the base of a large chimney, wall foundations, and parts of a stone cellar.

Charred planks and other debris indicate that the house was destroyed in a fire, sometime after the former president sold Highland in 1826. While historians have not been able to find newspaper articles mentioning a fire, later stories do mention that Monroe's estate was destroyed and a new structure was built.

This new find forced historians to re-think everything they knew about Monroe’s life at Highland, History.com reports. Previously, they had believed that the standing cottage was the remaining half of a larger home lived in by Monroe. However, they noted that its architectural features made it too advanced to have been built in 1799, when Monroe first moved to Highland. Meanwhile, they were skeptical that a U.S. president—even the down-to-earth son of a wood craftsman—would embrace such rustic accommodations.

The Highland team used tree-ring dating to date the cottage, and found that it was built between 1815 and 1818. This meant that the unearthed mansion probably served as Monroe’s main quarters; the smaller house was likely a two-room lodging that Monroe once described in an 1818 letter to his son as a guest house.

The new discovery was announced this week, just in time for James Monroe’s 258th birthday on April 28. In the mean time, Highland officials say that archaeologists will continue to explore the plantation's grounds for more insights into the president’s past.

“Surprisingly, this home of the last of our founding presidents has so much that remains to be explored archaeologically," Bon-Harper said. "The positive identification of the current house as the 1818 building confirms the interpretation of the archaeological remains as the house that Monroe and his family lived in beginning in November 1799. Future interpretation on site will incorporate the new revised understanding of the guest house while we continue archaeological research of Monroe’s main house.”

Check out a few pictures of the excavation process below, courtesy of James Monroe's Highland.

© 2016 Larry Bouterie

James Monroe’s Highland

[h/t The Washington Post]