He initially received permission from the Meskwaki people to mine the lead in 1788,[3] which was confirmed by the Spanish, who gave him a land grant in 1796.

[citation needed] After his death, the Meskwaki built a log crypt for Dubuque, which was replaced in the late 19th century by an imposing stone monument.

Dubuque was also a generous man who spent lavishly on many friends, which had the unfortunate effect of keeping him in debt during the later part of his life.

Though Dubuque's actual skull now lies buried under many feet of concrete, Taylor was able to use the multiple 1887 photographs, along with historic and anthropological inputs to create a reasonable depiction of his appearance in life.

The facial reconstruction images are on display at the National Mississippi River Museum & Aquarium in Dubuque, Iowa.