At first, no one noticed. Severus didn't often offer conversation from the frame that Harry Potter had insisted be placed in the head office. It was the portrait of Albus Dumbledore that first worried that something was wrong beyond the usual standoffish silence.
The discovery led to a steady stream of people through the office. Everyone from students to unspeakables trying to figure out why the portrait of Severus Snape had seemingly frozen. The magic was still as strong as it had been at its creation. In fact, the ambient magic of Hogwarts seemed to have made it stronger since the time it was carefully hung from the wall. The life within had simply faded and no amount of magic was bringing it back.
They decided to leave it as it was, a muggle-like portrait of a dour man resting in a comfortable chair. A Hogwarts professor and headmaster now forever at peace.
