The Savannah History Museum received 17 cannons on Wednesday that experts believe sank to the bottom of the Savannah River during the American Revolution and remained underwater for nearly 240 years.

The artifacts were discovered in 2021 when a dredging operation to deepen Savannah's shipping channel pulled up a cannon. Workers subsequently recovered a total of 19 cannons from the riverbed just downstream from Savannah, where Georgia was founded in 1733 as the last of Britain's 13 American colonies.

Archaeologists believe the cannons date to the 1779 siege of Savannah, when British forces scuttled at least six ships in the river to block approaching French vessels carrying colonial troops. The subsequent land battle was one of the bloodiest of the Revolutionary War, with British forces killing nearly 300 colonial fighters and their allies.

After recovery, 17 of the cannons were sent to Texas A&M University's Conservation Research Lab for cleaning and preservation. The process took years, as each cannon emerged covered in thick crusts of mud and minerals. Most arrived with wooden plugs still sealing their bores, which contained cannonballs and gunpowder charges.

Radiocarbon dating of the wooden stoppers placed them in the late 1700s. Experts in London determined three cannons were likely forged by the British military, while the rest appeared to be of French design but lacked identifying markings. Researchers suspect these may have been cast in America during the war period.

The cannons, weighing up to 1,500 pounds each, will be part of a new exhibit on Savannah's role in the American Revolution, scheduled to open during Fourth of July weekend as part of America's 250th birthday celebration. Two cannons remain in their uncleaned state for display, while the others have been treated with paint and wax to prevent corrosion.