The Hungarian Prince theory has been discounted as no evidence of any relationships exists in written records or DNA.
"The Red Book of the Menteiths" clearly discounts the Hungarian Prince as a myth likely formed to give status to the Drummond origins.
Indeed, one "Johannes De Drumon", said to have died in 1301, was buried in Inchmahome Priory which was founded by the Menteiths.
He had been created Duke of Perth, Marquess of Drummond, Earl of Stobhall, Viscount Cargill, and Lord Concraig in 1701 by the exiled Jacobite claimant to the British thrones, recognised by adherents of the Royal Stuarts as King James III and VIII.
He did not succeed, however, in removing the attainder of 1716, but was created by George III of the Hanoverian dynasty, in 1797, Lord Perth, Baron Drummond of Stobhall, in the Peerage of Great Britain, which title became extinct on his death in 1800.
Upon his death in 1840, he was succeeded in his peerage titles by his nephew, George Drummond, who had embraced the Protestant faith.
In 1853, the sixth Duke of Melfort, George Drummond, was by Act of Parliament deemed the 5th Earl of Perth, and the previous attainder was reversed.