Norbert, the Internet's Favorite Therapy Dog, Dies at 15: 'His Spirit Will Live On Through Our Smiles'

The world is saying goodbye to Norbert, the therapy dog.

On Monday, Jan. 27, his human mom, Julie Steines, shared in an update on Instagram that the internet-famous pup peacefully died the night before, “wrapped in the warmth of my arms.” She had said in previous posts that Norbert was “unexpectedly hospitalized” for elevated kidney markers earlier in the week.

“At only 3 pounds, he showed us all the importance of making others smile,” Steines included. “It was the honor of a lifetime to be entrusted to oversee his time here on earth.”

Steines adopted Norbert in 2009 when he was only four months old, training him herself to become a certified therapy dog by the time he was 1. The pup worked for 13 years helping make others smile — including countless patients at the Children’s Hospital Los Angeles, where he was named the tiniest therapy dog out of more than 100 enrolled in the hospital’s Amerman Family Foundation Dog Therapy Program.

“[The best part of Norbert’s work] is seeing the way that people respond to him,” Steines told PEOPLE in 2016, adding that he “can change the energy” of a room.

But his in-person work was only the beginning: Norbert also gained an international audience thanks to his social media presence, where he regularly showcased his kindness and fluff to his nearly 1 million Instagram followers.

The pup has even been featured in a series of children’s books, appeared on Today and Good Morning America, and was photographed for the covers of several pet magazines, including Animal Wellness Magazine, The WAG, Groomer to Groomer, and FIDO Friendly.

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories.

Throughout Norbert's life, he and Steines were involved in a variety of philanthropic efforts in addition to his regular animal therapy work. According to his website, the pair donated over 4,500 plush toys to Toys for Tots and other charitable organizations.

“Norbert made this world a better place, and his spirit will live on through our smiles in his community, the Norberthood,” wrote Steines in her Instagram post. “We feel the love and appreciate the prayers and support from each of you around the world. It means more than words can say.”

Read the original article on People