He was the prince who helped make the Rolling Stones as rich as kings.
Prince Rupert Loewenstein, the band's former business manager who helped the Stones churn their musical talent into mountains of gold, died Tuesday in a London hospital. He was 80 and had Parkinson's disease, said his friend Hugo Vickers.
The Oxford-educated aristocrat — whose full name was Prince Rupert Ludwig Ferdinand zu Loewenstein-Wertheim-Freudenberg — advised the Stones for almost four decades beginning in 1968.
He was introduced to Mick Jagger by a mutual friend at a time when the Stones were eager to extricate themselves from their relationship with American manager Allen Klein.
"Rupert was a merchant banker, very pukka, trustworthy," Keith Richards said in his autobiography "Life."
Loewenstein saw the Stones through their labyrinthine legal dispute with Klein, masterminded their year of tax exile in the south of France in the 1970s and oversaw their transformation into a formidable money-making machine that pioneered the lucrative mega-tour with the "Steel Wheels" extravaganza in 1989.
"He is a great financial mind for the market," Richards told Fortune magazine in 2002. "He plays that like I play guitar .… As long as there's a smile on Rupert's face, I'm cool."
Born in Majorca in 1933, Loewenstein studied medieval history at Oxford University before becoming a stockbroker and banker. Despite their very different backgrounds, Loewenstein and Jagger "absolutely clicked," Vickers said, and the prince became closely involved in the band members' lives.
"He had to get them out of trouble now and again," Vickers said. Loewenstein advised Jagger during his divorce from first wife Bianca and was godfather to the singer's son James.
Despite his close relationship with the band, Loewenstein always insisted he didn't like rock 'n' roll. He said that distance let him view the band's affairs "calmly, dispassionately, maybe even clinically — though never without affection."
Loewenstein worked with the band until 2007 and last year published a memoir, "A Prince Among Stones."
Jagger was not amused, telling a newspaper, "I don't think your ex-bank manager should be discussing your financial dealings and personal information in public."
Vickers remembered Loewenstein as "a tremendous bon viveur" who threw grand balls and parties at his home in the wealthy London suburb of Richmond and counted Princess Margaret among his friends.
He is survived by his wife Josephine, two sons and a daughter.