On the night of March 11, 1437, Korean astronomers recorded a strange light low in the sky, in the tail of the constellation Scorpius. It must have been at least as bright as the North Star, Polaris, maybe even as bright as the stars of the Big Dipper. Fourteen days later, the light disappeared.
Source: Gizmodo – Over 500 Years Later, Astronomers Solve an Explosive Stellar Mystery