When was promethium first discovered?

Promethium was first identified in 1945, when Jacob A. Marinsky, Lawrence E. Glendenin, and Charles D. Coryell isolated it from uranium fission products. It is one of the rarest naturally occurring elements on Earth and has no stable isotopes. The element was named after Prometheus from Greek mythology, who brought fire to humanity. Promethium was a late addition to the periodic table because it is very difficult to find in nature.