sentences:  Modern understanding that the Crab Nebula was created by a supernova traces back to 1921, when Carl Otto Lampland announced he had seen changes in the nebula's structure.This eventually led to the conclusion that the creation of the Crab Nebula corresponds to the bright SN 1054 supernova recorded by ancient astronomers in AD 1054.The Crab Nebula was first identified in 1731 by John Bevis.