Actor Stephen Boyd, best known for his role as Messala, Charlton Heston's chariot-racing opponent in "Ben Hur," collapsed while playing golf and died of heart failure Thursday.He was 49.

Mr. Boyd's press agent said the actor was golfing with his wife, Elizabeth, when he collapsed. Mr. Boyd was rushed to a hospital and died about two hours later.

Born William Miller near Belfast, Ireland, Mr. Boyd played in dozens of films as a Hollywood contract actor and costarred with some of the most famous actresses in the movie industry.But he never quite attained star status.

Mr. Boyd, a ruggedly handsome 6-footer with a superb physique, began his theatrical career in radio programs in Belfast at age 16.

He went to London where he worked as a doorman for a theater and as a cafeteria attendant. Shortly afterward, he was chosen to help actors on stage during the British film academy awards.

He was noticed by actor Michael Redgrave, who was presenting the awards. Redgrave gave him a letter of introduction to the head of a repertory company. Mr. Boyd won an audition and was hired immediately.

He worked in British theater for two years and then began working in television.

He was signed by London Films, which gave him a number of small parts and then lent him to 20th Century Fox. He received his first prominent role in "The Man Who never Was" and was given a long-term contract.

"I don't know what goes into being a star," he told an interviewer at one time. "Perhaps it is the capacity to explain the character and story to any audience, in any language, in any country."

He appeared in about 50 films, including "Island in the Sun," "The Best of Everything," "The Oscars," "Fantastic Voyage," "Fall of the Roman Empire," "Jumbo," "Imperial Venus," "The Inspector" and "Genghis Khan."

He played opposite such actresses as Brigitte Bardot, Susan Hayworth, Joan Crawford, Gina Lollobrigida, Sophia Loren, Ava Gardner and Raquel Welch.

Mr. Boyd was never nominated for an Oscar but won the Golden Globe award of the Hollywood Foreign Press Association for his role in "Ben Hur," filmed in 1959. His career peaked in that film, and the chariot race sequence, considered a film classic, was entered in the Motion Picture Academy's archives in Hollywood.

After a role in "The Oscars" in 1966, Mr. Boyd decided to work with independent producers and began a new career in foreign-produced films.

He recently returned from Hawaii where he played a guest role in the television series "Hawaii Five-O."

Mr. Boyd's agent said the actor had no history of heart trouble.

"he liked to find as many different golf courses as he could play on. Anywhere he went to film, he would seek out a new golf course," the agent said.

Mr. Boyd is survived by his wife, Elizabeth, who was his second wife.