Per Olov Enquist, the acclaimed Swedish author known for his dark novels, has died at 85, the Guardian reports. He died after a “long illness,” his family said.

Enquist, who started his career as a journalist, published his first novel, The Crystal Eye, in 1961. Seven years later, he released The Legionnaires, which won the Nordic Council Literature Prize the following year.

His books were widely translated, with several published in English-language editions, including The Royal Physician’s Visit, Lewi’s Journey, and The Book About Blanche and Marie. A reviewer for Kirkus called him “one of the world’s most underrated great writers.”

“He was a novelist of immense stature and range; he was also all his life a playwright; and he was a spellbinding speaker at literary events,” said British publisher Christopher MacLehose.

Enquist was one of the writers of the acclaimed 1987 film Pelle the Conqueror, starring Max von Sydow, which won the Academy Award for Best Foreign Language Film. The movie was based on the 1910 novel by Danish author Martin Andersen Nexø.

Enquist’s most recent novel, The Parable Book, was published in 2013.

On Twitter, Christopher Lars Aqurette paid tribute to the author, writing, “Few authors have meant more to me than him. I’ve never been able to put my finger on it, but there is such poetry in his prose—even when he wrote about contemporary politics and historic events.”

Michael Schaub is a Texas-based journalist and regular contributor to NPR.