George Lascelles, who was born into British royalty and made himself a king in the opera world, died July 11 at his home near Leeds, England. He was 88. A representative of his estate did not disclose the cause of death.

The seventh earl of Harewood, he was the grandson and nephew of kings and a first cousin of Queen Elizabeth II. But, as the British newspaper the Guardian wrote in a 1985 profile of Lord Harewood, “he thinks this very boring.”

Lord Harewood found the greatest majesty not in the royal court but in the opera house. The depth of his musical expertise earned him appointments at prominent institutions such as London’s Covent Garden and what became the English National Opera, where he served as managing director in the 1970s and ’80s.

“Never before,” the London Sunday Times once wrote, “has a member of the royal family played so active a part in the artistic life of Britain.”

Outside the theater, Lord Harewood edited and revised “The Complete Opera Book,” a gargantuan reference guide to operas and their synopses. Its original author, New York Herald music critic Gustav Kobbe, was killed in a boating accident off Long Island in 1918.

Lord Harewood’s first updated version of the book appeared in the 1950s, with many more to follow. His enthusiastic writing style — a welcome change from the deadly prose that stares up at music lovers from the pages of many other opera books and programs — helped the volume achieve an almost eternal shelf life.

The work is a “constant companion” for opera professionals and devotees, said Roger Pines, the dramaturge of Lyric Opera of Chicago. The only other book in its class, Pines said, is the definitive New Grove Dictionary of Music and Musicians — as it happens, a book that played more than a small role in Lord Harewood’s life.

George Henry Hubert Lascelles was born Feb. 7, 1923, in London. His mother, Princess Mary, was the daughter of King George V. As a child, he participated in the funeral of one king (his grandfather) and the coronation of another (his uncle George VI).

During his childhood he found himself drawn to classical music, but he could have hardly predicted that it would carry him through World War II.

In 1942, at 19, he was commissioned into the Grenadier Guards and was sent to Tunisia, Algiers and Italy. Lord Harewood’s duties in Naples left time for him to attend matinees at the San Carlo theater, where the show went on despite the war, and where he discovered his love for the opera.

Music turned out to be good company during a trying time. After being injured near Perugia in June 1944, Lord Harewood found himself in prisoner-of-war camps in Germany, including Colditz Castle.

Talking to a Guardian reporter about the fact that his injury had taken place June 18 — the date on which two earls before him had been injured, one at Waterloo and one in 1915 — he said this:

“Must be more to it than coincidence. Don’t know what it is. Must be. My only superstition is that I won’t defy any superstition. . . . I don’t like to defy the fates that way, I think the fates get it back on us all the time.”

It was a philosophy that could be developed if not from reading Shakespeare, then from sitting through a few operas.

In fact, during his imprisonment, Lord Harewood read the multivolume Grove’s Dictionary.

After the war, he studied English literature at King’s College, his work occasionally interrupted by royal duties.

After graduating, Lord Harewood worked as an opera critic. In 1950, he founded Opera magazine, which he used to bring opera to people in England and, as the publication grew in popularity, around the world.

In 1949, he married Marion Stein, an Austrian-born pianist. That marriage ended in divorce.

In 1967, after receiving permission from his cousin, the queen, Lord Harewood married Patricia Tuckwell, who had given birth to his son Mark three years earlier. They survive, as do three sons from his first marriage, David, James and Jeremy; a stepson, Michael Shmith; 14 grandchildren; and five great-grandchildren.

In a preface to “The New Kobbe’s Complete Opera Book,” Lord Harewood wrote: “While recognizing that a blind faith in the future of opera would be totally out of place . . . I cannot forget that the original notion behind opera is still valid: dramma per musica, drama through music. . . . So long as man has time for the performing arts, he will want to combine music and drama in an effort to make the amalgam amount to something not quite the same as either on its own.”