Arnold Friberg, a widely popular artist of historical and religious scenes whose painstaking quest for stunning realism led him to Valley Forge, Pa., on a winter’s day to paint what became a famous portrait of George Washington praying in the snow, died Thursday in Salt Lake City. He was 96.

The cause was complications of hip surgery, his daughter-in-law Jayna Friberg-Cleamons said.

Mr. Friberg (pronounced FREE-berg) was probably best known for the “The Prayer at Valley Forge,” which depicts Washington kneeling beside his horse while his army winters at Valley Forge. To ensure utter accuracy, he went to the Smithsonian Institution to study Washington’s actual uniform.

And when it came time to paint, he stood on the banks of the Schuylkill River in the bitter cold near the spot where he imagined Washington kneeled. He removed his gloves.

“It was deserted, the wind moaning through the great trees, silent, lonely, cold,” he later recalled.