The heir to the British throne, Prince Charles, is facing harsh criticism for a letter he wrote in 1986, blaming “the influx of foreign, European Jews” for unrest in the Middle East.

In the letter, which was recently unearthed by the Daily Mail on Saturday, Prince Charles also asked whether an American president would “have the courage” to stand up to the Jewish lobby to put an end to terrorism in the Middle East.

“I now begin to understand better their [Arabs’] point of view about Israel. Never realised they see it as a U.S. colony,” the prince told close friend Laurens van der Post in the 1986 letter. It was reportedly written after he and his late then-wife Princess Diana toured Saudi Arabia, Bahrain, and Qatar.

“I now appreciate that Arabs and Jews were all a Semitic people originally and it is the influx of foreign, European Jews (especially from Poland, they say) which has helped to cause great problems,” Prince Charles continued, referring to migration patterns during the 20th century.

“Surely some U.S. president has to have the courage to stand up and take on the Jewish lobby in U.S.? I must be naive, I suppose!” the 38-year-old Prince Charles wrote more than thirty years ago.

A spokeswoman for Clarence House said the prince was expressing the opinions of people he had met on the trip, rather than his own.

“He was sharing the arguments in private correspondence with a long-standing friend in an attempt to improve his understanding of what he has always recognised is a deeply complex issue, to which he was coming early on in his own analysis in 1986,” the representative said.

“Over the years, the prince has continued his study of the complex and difficult themes he referenced here. He has built a proven track record of support for both Jewish and Arab communities around the world and has a long history of promoting interfaith dialogue and cultural understanding,” she added.