When people think of Civil War artifacts, they may picture cannonballs or 19th-century rifles. An item recently dug up from the ruins of a fort in Virginia isn't a weapon, but it was likely viewed by Union soldiers as a source of protection. The artifact—a glass jug filled with rusted nails—is believed to be a witch bottle, or a talisman used to ward off evil spirits, Live Science reports.

Archaeologists uncovered the so-called witch bottle during a dig organized by the Virginia Department of Transportation at Redoubt 9, a Civil War-era site that sits in the median between exits 238 and 242 on Interstate 64. The fortification was constructed by Confederate soldiers in 1861 and taken over by Union troops later in the war. The glass bottle was made in Pennsylvania, which indicates it was probably left there by a Union soldier from the Pennsylvania cavalry that likely occupied the site.

It's easy to mistake the bottle for trash. Archaeologists found it near the fort's hearth and initially assumed it had been used by soldiers to store nails for repairs. But to someone familiar with old English superstitions, the artifact tells a much more interesting story.

In 16th and 17th century England, it was common for people to use witch bottles to protect themselves from curses placed on them by the witches that were feared to be everywhere at the time. The "cursed" would fill a glass or ceramic container with bent pins or nails and even add urine and human hair in some cases. They would then bury the bottle near the house's hearth, the idea being that the heat would cause it to shatter, thus breaking the witches spell.

This type of practice was much less common in Civil War-era America, but the artifact shows that the superstition introduced to the country by British immigrants had survived into the 19th century. It also illustrates the fear soldiers must have felt at the height of the war and the lengths they took to ease those worries.

“There were a lot of casualties and fear during this period," Joe Jones, the director of the William & Mary Center for Archaeological Research, which works closely with the Virginia Department of Transportation on archaeological work, said in a statement. "The Union troops were an occupying force in enemy territory throughout most of the war, so there were plenty of bad spirits and energy to ward off.”

According to the WMCAR, this witch bottle is one of fewer than a dozen that have been discovered in the United States.

[h/t Live Science]