Richard Adams, the author of the iconic children’s book, Watership Down, has died at age 96.

He had been ill for some time, but died peacefully at 10:00 pm on Christmas Eve. His daughter, Juliet Johnson, was with her father when he died, and took comfort that they had had a long, loving talk the night before. She said that “It was absolutely typical of Dad that he would choose such a night on which to leave this world,” because Christmas Eve is a magical night when “traditionally the animals and birds can talk.”

Watership Down was Mr. Adams’ first book; he was 52 when it was published. He first conceived the story of a group of rabbits that must flee their home in order to entertain his daughters during a long car ride. It was his daughters that urged him to put the story down on paper, a project that took the London civil servant (who wrote environmental reports for a living) two years to accomplish.

The New York Times calls Watership Down “a timeless allegory of freedom, ethics and human nature,” but it was not an immediate success, suffering many rejections before finally being published in a modest run by Rex Collings, Ltd, a small publishing firm. However, the critics loved the book, likening it to the works of J. R. R. Tolkien and A. A. Milne. It quickly won the Carnegie Medal in Literature followed by the Guardian Children’s Fiction Prize; upon its US publication, it topped the New York Times‘ bestseller list for eight months, allowing Mr. Adams to leave the civil service and become a full time author. (The Guardian reports that Watership Down is one of the bestselling children’s book of all time, selling over ten million copies.)

According to his daughter, Mr. Adams had taken “great comfort” in the knowledge that a new animated series of the book is slated to air in 2017 (co-produced by the BBC and Netflix). James McAvoy, Sir Ben Kingsley, Gemma Arterton, Nicholas Hoult and John Boyega are merely a few of the vocal talents that will be gracing the new adaptation.

Mr. Adams is survived by his wife of 67 years, Elizabeth, and his two daughters, Juliet and Rosamond.