There have only been eight recorded finds of such seals in the UK, which were placed on important documents by the Pope.
The ninth was discovered by those behind new business, Metal Detecting Holidays, near Oswestry, and dates back to the time of Pope Pius II, from about 1400 AD.
It is the second find for the Whittington based holiday company this month, after US television star Jocelyn Elizabeth’ found a rare ‘pierced’ French 1553 Silver Teston coin.
The Relic Recoverist presenter and other media detectorists including personalities from the National Geographic Channel’s Diggers who were invited by Chris Langston one of the co-founders of the company to try a holiday out for themselves.
Because the coin has been pierced, possibly to use as jewellery, it could be deemed to be treasure trove, Mr Langston said.
“Silver and gold pierced coins from the Iron Age through the Early Medieval period are not found in hoards of other coins, meaning they were taken out of circulation. Therefore they should be considered as items of jewellery and reported as potential treasure, even if there are no other modifications on the coins,” he said.
“This coin is a Rare Kingdom of France, Henry II, silver milled teston of 1553. Milled coinage was experimental in the 16th century and would not be generally adopted in France until the reform of 1640-42.”
He said that the papal seal or ‘bull’ as it was known had been in use since the 6th century.
They were used on importance documents to ensure their authenticity was above suspicion.
Mr Langston added: “Since the 12th century, papal bulls have carried a leaden seal with the heads of the Apostles Saint Peter and Saint Paul on one side and the pope’s name on the other.”
He said that from the 13th century, papal bulls were only used for the most formal or solemn of occasions.
The Metal Detecting Holidays company was set up Mr Langston, Louise Idoux and John Flaherty.