BA retired engineer from Tyneside and a financial director from Berkshire have been named as "alternative" heirs to the English throne.
Albert Turnbull's lineage goes back to King Alfred
Albert Turnbull and Mark Golledge were identified in a campaign to find out who could have been King if William the Conqueror had been defeated.
English Heritage asked claimants to prove their family trees back to 1066.
Mr Turnbull, from Gateshead, and Mr Golledge, from Berkshire, were among 500 global-wide respondents.
Claimants had to prove links to either King Harold, Edward the Confessor, Edgar the Aetheling or Alfred the Great.
English Heritage eventually shortlisted 150 people who included claimants from as far afield as the USA, Australia and Norway.
Mr Turnbull was able to trace his lineage back to St Margaret and King Alfred but also to William the Conqueror, meaning his family may have had a claim regardless of the result at the Battle of Hastings.
He said he was shocked by the news but the Prince of Wales need not be concerned that he would make any claim to the throne.
Mr Turnbull said: "He's my 23rd cousin. He seems to have a sense of humour. I think he would take it in good fun."
Mr Golledge traced his family back to Alfred the Great through the "Stemmata Chicheleana" historical documents.
Published in 1765, they record all the descendants of Archbishop Henry Chichele, the founder of All Souls College, Oxford - who is related to Mr Golledge.
"My family and I are very proud of our ancestry and very fortunate to have such a unique reference to illustrate our heritage," he said.
The research marked the opening of a new £2.3m visitor centre at 1066 Battle of Hastings, Abbey and Battlefield in East Sussex.
A spokesman for English Heritage said: "The claims are still coming in. People are going into extraordinary detail, sending CD roms and huge family trees."