Calamity Jane was a real life frontierswoman, sharpshooter, and raconteur born in Princeton, Missouri in 1852. She was known for many extraordinary exploits and adventures and for being an acquaintance of Wild Bill Hickock.
Wild Bill Hickock's death is referenced by Calamity Jane (Norma Crane). This would place this episode sometime after his death on August 2, 1876.