BUCHAREST, Romania — Britain’s Prince Charles joined in a traditional folk dance Thursday during a visit to Romania, the first stop in a three-nation trip seen as an effort to reassure European Union nations that Britain remains a close ally.

The prince’s nine-day tour is designed to “highlight the U.K.’s relationship with European partners” in areas such as military ties and combating human trafficking, according to his official website.

Britain formally triggered two years of negotiations to leave the EU on Wednesday.

Romania’s ambassador to Britain, Dan Mihalache, said Romanians were concerned about their status after Britain formally leaves the bloc. He estimated there are up to 500,000 Romanians living in Britain – many more than the 190,000 registered there.

He said the embassy has advised Romanians to get a resident’s permit and to make sure they were working on a legal contract.

Meanwhile, Charles visited an open air museum in Bucharest that features rural houses from Romania’s different regions. He joined women and girls dressed in embroidered peasant blouses in a traditional jig known as the “hora.”

Charles is enamored of Romania’s rural traditions and owns two properties in Transylvania. He even boasts of sharing common lineage with Vlad the Impaler, the 15th century Romanian prince who was the inspiration for Dracula.