Stephen Sondheim, the composer and lyricist widely regarded as one of the most influential figures in musical theater history, has died, according to The New York Times. Sondheim was 91 years old.

Born and raised in New York, Stephen Sondheim was mentored at a young age by Oscar Hammerstein. Following college, he started his career as the lyricist of the hit musicals West Side Story and Gypsy. Between 1970 and 1981, he collaborated with Hal Prince on some of his earliest successes as the writer of both music and lyrics, including Company, Follies, Sweeney Todd, and Merrily We Roll Along. In the ’80s and ’90s, Sondheim collaborated with James Lapine on Sunday in the Park With George and Into the Woods.

Sondheim was widely decorated throughout his career for his achievements in music and theater. He won eight Tony Awards, including a Lifetime Achievement award; he was awarded the 1985 Pulitzer Prize for Drama for Sunday in the Park With George; he received the Kennedy Center Honors in 1993; and he also won eight Grammy Awards, including the Trustees Award throughout his career. In 1990, Sondheim won an Oscar for his song from 1990’s Dick Tracy.

Sondheim’s legacy remained a cornerstone of popular culture in recent years. Into the Woods was adapted into a star-studded film, a West Side Story was adapted by Stephen Spielberg, “Being Alive” was sung by Adam Driver in Noah Baumbach’s Marriage Story, and Company was lampooned by John Mulaney and Seth Meyers in Documentary Now.

Sondheim continued working until the end of his life. Just two months ago, he spoke with Stephen Colbert for The Late Show With Stephen Colbert. Sondheim told Colbert that he was working on a new musical called Square One. Actor Nathan Lane said that he, Bernadette Peters, and others did a reading of the musical, which Lane called “very exciting.”