The ceiling is that of the Sistine Chapel, the large papal chapel built within the Vatican between 1477 and 1480 by Pope Sixtus IV, for whom the chapel is named. It was painted at the commission of Pope Julius II. The chapel is the location for papal conclaves and many other important services.

Answer this question: who was pope when the sistine chapel was painted? Let's think fast. Stream of consciousness:
The relevant information is: The ceiling is that of the Sistine Chapel, the large papal chapel built within the Vatican between 1477 and 1480 by Pope Sixtus IV, for whom the chapel is named. So the final answer is Pope Sixtus IV.