Erich Segal, a one-time classics professor whose sentimental 1970 screenplay and novel “Love Story” became a pop-culture phenomenon, died Sunday of a heart attack at his home in London. He was 72 and had battled Parkinson’s disease for 25 years.

Segal, who taught Greek and Roman literature at Yale University, might have been an unlikely author of a heart-tugging tale of doomed romance, but his story captured the spirit of the time, and its signature line became a catch phrase: “Love means never having to say you’re sorry.”

The 1970 film, which starred Ali MacGraw and Ryan O’Neal and became a huge hit, was in production before Segal reworked it as a novel. Although Segal’s work resonated with the public, critics almost uniformly lambasted it.