Image copyright Hay Castle Trust Image caption The 4.5 stone ball could date back to the 13th Century

A large stone ball, thought to have been launched from a medieval catapult during a siege of Hay Castle, has been found by archaeologists.

It was found during excavations at the Powys castle, and is 1ft (29cm) wide and weighs 4.5 stone (28.5kg).

The ball was found 1.3ft (40cm) deep in the east wing of the site.

It is thought it was launched from a large wooden catapult, known as a trebuchet. These were first used in Britain in about 1217.

There are records of various sieges at Hay Castle throughout the 1200s, and it is possible that this stone dates from the Barons War of 1263 to 1266, according to Hay Castle Trust.

Dr Chris Caple, former associate professor of archaeology at Durham University, said the trebuchets were "not easily constructed".

"This means that they usually indicate royal forces, or those of a very wealthy lord," he explained.

Similar trebuchet balls were found at Dryslwyn Castle in Carmarthenshire.

Attackers would also use dead animals, human bodies, excrement and burning items as ammunition, the trust said.