William Sherley "Old Bill" Williams was a noted mountain man and frontiersman, known as Lone Elk to the Native Americans. Fluent in several languages, Williams served as an interpreter for the government and led several expeditions to the West. He married into the Osage Nation, having two children who both married John Allen Mathews.

A mountain man is an explorer who lives in the wilderness and makes his living from hunting and trapping. Mountain men were most common in the North American Rocky Mountains from about 1810 through to the 1880s. They were instrumental in opening up the various emigrant trails allowing Americans in the east to settle the new territories of the far west by organized wagon trains traveling over roads explored and in many cases, physically improved by the mountain men and the big fur companies, originally to serve the mule train-based inland fur trade.