Charles Simic, the poet known for his vivid imagery and sometimes dark wit, has died at 84, the Associated Press reports.

Simic was born in Belgrade, capital of Yugoslavia at the time. His family was frequently displaced because of World War II, and he moved to the U.S. with his family when he was 16.

Simic was educated at New York University, and published his first poetry collection, What the Grass Says, in 1967. Dozens more would follow, including School for Dark Thoughts, Unending Blues, and Pyramids and Sphinxes. His 1990 collection, The World Doesn’t End, won the Pulitzer Prize.

He won the Academy of American Poets’ Wallace Stevens Award in 2007, the same year he was appointed U.S. Poet Laureate.

Simic’s admirers paid tribute to him on social media. On Twitter, author Meghan O’Rourke wrote, “I’m heartbroken to learn that Charles Simic has passed. Charlie was such a dear friend, a bon vivant in the best sense, and a generous soul. I would not be the poet or editor I am today without his friendship.”

Poet and novelist Ben Purkert tweeted, “Incredibly sad to hear about Charles Simic’s passing. I’ve never met anyone who cared as deeply about levity. He was so serious and so funny and so full of poetry in his bones.”

Michael Schaub, a journalist and regular contributor to NPR, lives near Austin, Texas.