Prince Charles is campaigning to save the forests of Transylvania, inspired by his ancestral links to Vlad the Impaler, the 15th century nobleman better known by his patronym, Dracula.
Rapid economic growth in Romania - which is now part of the EU - means that the forests of the Carpathian Mountains are under threat from development and logging.
The Prince is calling for the forests, some of the last untouched wilderness areas in Europe, to be protected before they are lost, like the woodland that once covered Britain.
He claims a family connection to the area through Vlad III, Prince of Wallachia, who earned the sobriquet Vlad the Impaler thanks to his favoured method of torture and execution.
The 15th century nobleman, notorious for his bloodthirsty campaigns against the Ottomans and fierce repression of his people, is a distant ancestor of Charles's great-grandmother, Queen Mary.
The total number of his victims is estimated in the tens of thousands, many killed by being impaled on huge metal stakes.
His reputation for cruelty is said to have helped inspire Bram Stoker's diabolical villain, Count Dracula.
In a new documentary about the Carpathian mountains, Charles makes fun of his ancestral links to 'Count Dracula'.
'The genealogy shows I am descended from Vlad the Impaler, so I do have a bit of a stake in the country,' he quipped.
The Prince has recently bought a five-bedroom house in the village of Zalanpatak, which is said to have been founded by one of his Transylvanian ancestors.
Charles is expected to use the 150-year-old home as an isolated holiday retreat, and it will be used as a guesthouse when he is not in residence.
The Prince first visited Transylvania in 1998 and has bought three properties there, including the Zalanpatak house and a £43-a-night guesthouse in the village of Viscri.
Traditional farming and building techniques used in the area are said to have inspired his plans for Poundbury, the Dorset village created by his Duchy of Cornwall.
He has since sold a manor near the medieval town of Sighisoara, while the Viscri and Zalanpatak guesthouses are managed by Count Tibor Kalnoky.
'It seems to me in Transylvania there is a combination of the natural ecosystem with a human cultural system,' the prince told the documentary, according to the Daily Telegraph.
'This extraordinarily unique integrated relationship is so hugely important. People are yearning for that sense of belonging and identity and meaning.'
If development goes ahead, Romania could end up barren like swathes of the Highlands of Scotland or Canada that were once dense with virgin forest, Prince Charles warned.
Two-hundred-and-fifty-thousand hectares of virgin forests are in urgent need of protection, according to Magor Csibi, country manager of the World Wildlife Fund's Danube-Carpathian programme in Romania.
The area, home to brown bears, lynx, wolves, and 13,000 other species, represents up to 65 per cent of Europe's remaining virgin forests.