Facebook co-founder and CEO Mark Zuckerberg has eschewed his atheist beliefs and now asserts that “religion is very important.”

Zuckerberg, whose Facebook profile once identified him as an atheist, revealed his change of heart on his social media network after he wished everyone on Dec. 25 a “Merry Christmas and Happy Hanukkah” from “Priscilla, Max, Beast and me,” referring to his wife, daughter and dog. When a commenter asked him, “Aren’t you an atheist?” he responded: “No. I was raised Jewish and then I went through a period where I questioned things, but now I believe religion is very important.”

He didn’t provide details about his faith. The title of his holiday greeting on Facebook was “celebrating Christmas.”

He and wife Priscilla Chan met with Pope Francis at the Vatican last summer and discussed how to bring communication technology to the world’s poor. Zuckerberg said at the time that he was impressed with the pope’s compassion.

“We told him how much we admire his message of mercy and tenderness, and how he’s found new ways to communicate with people of every faith around the world,” Zuckerberg posted. “It was a meeting we’ll never forget. You can feel his warmth and kindness, and how deeply he cares about helping people.”

Zuckerberg has also cultivated an interest in Buddhism, which his wife practices.

During a 2015 trip to China, Zuckerberg visited the Wild Goose Pagoda in Xi’an and “offered a prayer for peace and health for the world and for my family,” Zuckerberg posted at the time, including a photo of himself kneeling in front of the Buddhist landmark.

He added: “Priscilla is Buddhist and asked me to offer a prayer from her as well. Buddhism is an amazing religion and philosophy, and I have been learning more about it over time. I hope to continue understanding the faith more deeply.”