Historians have uncovered an 18th-century French plan to invade Britain with an American army during the War of Independence.

The plan, which was drawn up by a French general, was to bring over 10,000 American soldiers and capitalise on a Britain that was distracted by the war on the other side of the Atlantic.

The general also proposed that the force include a corps of American Indians, or “sauvages”, as he termed them, that would strike terror into the British.

The document was drawn up by Charles-François Dumouriez when commander at Cherbourg and bears a pencil note saying it came from the papers of General Barthélemy Scherer, briefly Minister of War.

The skull of an American soldier who died on a British prison ship will be reburied after undergoing forensic study.

A 1907 catalog of the New Haven County Historical Society listed several rare and odd items, including a necklace from an Egyptian mummy, slave chains, a small block of wood from the Old South Bridge in Concord, Mass., which the British guarded at the start of the Revolutionary War.

But lot 23 in the inventory — “a skull of an American soldier, one of 42 who died of the 200 in a destitute and sickly condition that were brought from a British prison ship … and suddenly cast upon the shore of the town of Milford on the 1st of January, 1777″ — has sparked contemporary patriots to ride to the rescue.