Brad Anderson, creator of the long-running one-strip comic Marmaduke, passed away Sunday. He was 91.

John Glynn, the president behind his syndicate Universal Uclick, confirmed Anderson's passing.

The cause of death is unknown currently, but was considered "unexpected" by the the National Cartoonists Society, who wrote a tribute to their fallen animator over the weekend. In their remembrance, they flourished upon Anderson's love for drawing. Cartooning his way through high school, he sold his first comic at 15 to Flying Aces Magazines. Though he served in the Navy after public school, he continued drawing through his WWII service. A graduate of Syracuse University in 1951, with a degree in advertising, he briefly worked within the field before focusing as a freelance cartoonist in 1953.

The year after, he began two strips: Grandpa's Boy, which ran through 1966, and Marmaduke. Anderson continued creating new strips of the 61-year-old comic with his son, Paul, up through his death. It was syndicated in 500 newspapers in 10 different countries, according to the NCS.

In addition to appearing on the newspaper pages, the titular Great Dane also found himself on television in the '80s during segments on the Heathcliff show. He was also the focus of the live-action film of the same name from 2010, with Owen Wilson providing the voice behind the Winslow family pet. Syracuse University exhibited his works the same year alongside fellow alums Greg Walker (Beetle Bailey) and Rob Armstrong (Jump Start).

Survived by his wife and three other children, he is also remembered by his hometown of Brocton, New York, according to The Buffalo News, with a memorial planned for the cartoonist. A fundraising event to make a bronze statue of Anderson and Marmaduke in their likeness is currently in the works moment by Daniel Schrantz, town supervisor of Portland, New York.