The City of Dubuque is one of the oldest settlements west of the Mississippi. Julien Dubuque was the first permanent settler in the area in 1785, which was then under Spanish control. He got permission from the Spanish and created the first lead mines in the area. France, and then USA, with the Louisiana Purchase, gained control of Louisiana, where Dubuque lay. The area became part of the Iowa Territory in 1838 and then part of the state of Iowa in 1846. After the lead sources where exhausted the economy shifted to industry and industry remained the cities' main income source even into the 1980's.