'Simpsons' Co-Creator Sam Simon Dies at 59

The Simpsons co-creator Sam Simon died on Sunday after a long battle with colon cancer, his foundation announced on Facebook. He was 59.

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"It is with much sadness that we must let you know that Sam Simon has passed over," they wrote. "We all miss him, and in his honor, we will continue bringing his vision to light through our work at The Sam Simon Foundation. We take comfort in knowing how many greetings he is receiving across that Rainbow Bridge. We love you Sam!"

The writer/producer reportedly passed away at his Los Angeles home, surrounded by his family and his dog. As an animal rights advocate who worked closely with PETA and various other animal welfare organizations, Simon's dog was an important part of his life. He continued to fight for the rights of animals up until his last days, most recently expressing his disappointment in Britney Spears for swimming with dolphins at a Las Vegas hotel.

Originally given three to six months to live when he was diagnosed in 2012, he fought valiantly. In November, Simon opened up about his illness in an interview with Maria Shriver, where he managed to be candid while holding onto his sense of humor.

"Cancer is a horrible disease," he said. "It's a fight. It's a journey. It's tough. But, if you want publicity, and if you want to pick up girls, then cancer is the greatest thing in the world."

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Simon developed The Simpsons with Matt Groening and James L. Brooks and led the initial team of writers, before leaving the show in 1993. "Sam helped establish the tone and world of the Simpsons in the early years of this landmark series, and his contributions live on. His philanthropy was well-known and a source of inspiration for many. We are deeply saddened by his passing," Fox Television said in a statement to ET. His fellow Simpons co-creators also spoke out.

"We will miss Sam’s phenomenal talents, sharp intelligence, and sly sense of humor. He is gone from our industry too soon," Matt Groening said.

Executive producer James L. Brooks issued this statement, "He was truly one of the great ones. He found so much outside the work to give him pleasure and left so much behind for others."

"He was a genius and a great humanitarian in ways public and private. I personally owe him more than can be repaid, but I will do my best to help every animal I can in his memory," Simpsons showrunner and executive producer Al Jean said in addition to tweeting.

His entire fortune -- valued at $100 million -- is expected to go to charity. Animal welfare and feeding the homeless were causes that were especially important to him. His Sam Simon Foundation's "Feeding Families" program alone feeds 400 families a day in Los Angeles.