The Lesems were a group of three brothers who were in Leadville briefly in the early 1880s. The brothers included Isaac, Louis and Samuel.[1]   Their parents were Solomon Lesem and Rebecca Mook, both from Germany.[2]   Isaac was born during 1847 in Hopkinville, Kentucky. Louis was next, born in 1849. In 1851, Samuel was born in Missouri.  Solomon and Rebecca also had a daughter, Celestine, in 1858.  Celestine eventually married Benjamin Wisebart and moved to Colorado.  In 1877, in Quincy, Illinois, Isaac married Harriet Bernheimer.  She was born in Buffalo, New York during 1853.[3]   By 1880, Isaac, Louis and Samuel had all moved to Leadville. The 1880 census does not show Harriet accompanying Isaac, and she may have initially stayed behind in Quincy, Illinois.[4]

Isaac does not appear in city directories, but he is in the 1880 census[5]  and appears in insurance advertisements up to January 1, 1881.[6]   Both Louis and Samuel appear in the 1881 and 1882 Leadville city directories.[7]   Louis is listed as a cashier for Travelers’ Insurance located at 200 Harrison Avenue.[8]  Samuel was an insurance agent at the same location.[9]   In October 1881, Louis was an attendee of the Simchas Torah Ball hosted by the Hebrew Ladies Benevolent Society.[10]   The pair cease to appear after 1882 in the directories.  However, between 1887[11]  and 1894,[12]  Samuel is listed as visiting Leadville from Denver several times for insurance purposes.

After leaving Leadville, Isaac eventually made his was to St. Louis where he died in March, 1928.[13]   His wife, Harriet died in November of the same year.[14]   Louis moved to Denver where he died in 1909.[15]   It is not known when Samuel died.[16]