Robert Fellowes, the uncle of Prince William and Prince Harry and brother-in-law to their mother, the late Princess Diana, has died. He was 82.

His obituary published on July 31 in The Times said that he died on July 29 of undisclosed causes. Fellowes married Princess Diana’s elder sister, Lady Jane Spencer, in 1978, and their brother Charles Spencer shared his condolences when the obituary was released.

“A total gentleman – in all the best meanings of that word – he was a man of humor, wisdom & utter integrity. I’m deeply proud to have been his brother-in-law,” he added.