A global search is under way for people whose ancestors might have had a claim to the throne of England.
Battle Abbey was built to commemorate the 1066 battle
English Heritage is advertising in newspapers round the world for people whose family tree may be traced as far back as the Battle of Hastings.
Some may be descendants of Edgar Aetheling, who arguably had a better claim to the throne than King Harold II, defeated at the battle in 1066.
"We have had a considerable response already," said Dr Tracy Borman.
"I suspect this is going to be quite big and we are going to have a lot of post coming to our office," she said.
Edgar was a relative of King Edward the Confessor but was only 10 when Edward died.
King Harold was crowned after claiming Edward had passed the throne to him on his deathbed.
"William the Conqueror also claimed Edward said he could have it, so there was a free-for-all really," said Dr Borman, English Heritage's learning director.
William crossed the English Channel from Normandy to defeat Harold at the Battle of Hastings, which was actually fought nearby at a spot in East Sussex now called Battle.
Dr Borman said descendants of other noblemen might also have had a claim to the throne.
"At that time, monarchy wasn't hereditary so if you were a great lord you could quite justifiably have had a claim," she said.
The search is linked to the opening of a new visitor centre at Battle Abbey next month.
"We are aiming to draw attention to what we think is the most important event in English history - the Battle of Hastings," said Dr Borman.
"Visitors will be able to go to the new visitor centre and actually trace their own ancestors, learn more about the battle and even try on some chain mail."
Exhibits at Battle Abbey lead visitors round the battle site
A team of genealogists will scrutinise claims from people who believe they can trace their family trees back to 1066.
"Family history is getting easier and easier to trace," said Dr Borman.
"The real revolution has been online - there are a huge number of websites, although not everyone will be able to go back 1,000 years."
The results of the search will be published on the English Heritage website.
"We would stress that we are not trying to put somebody else on the throne, but we will give them all credit on our website which I am sure is just as good," said Dr Borman.