According to Daniel, Belshazzar was the Babylonian king who saw mysterious writing appear on a wall during a feast.
Daniel 5 describes Belshazzar holding a great banquet for his nobles and using sacred vessels taken from the Jerusalem Temple. During the feast, a hand appeared and wrote words on the wall. The king’s wise men could not interpret the message, so Daniel was summoned.
Daniel read the words as Mene, Mene, Tekel, and Parsin and interpreted them as a judgment on Belshazzar’s reign. The chapter ends with Belshazzar being killed and Darius the Mede receiving the kingdom.
The expression “the writing on the wall” comes from this story. Belshazzar is distinct from Nebuchadnezzar, the Babylonian ruler featured earlier in Daniel. Historical sources also preserve a Belshazzar who was the son of Nabonidus and served as regent, a detail that differs from some elements of the biblical narrative.