Des Moines is the capital and the most populous city in the US state of Iowa. It is also the county seat of Polk County. A small portion of the city extends into Warren County. It was incorporated on September 22, 1851, as Fort Des Moines which was shortened to "Des Moines" in 1857. It is named after the Des Moines River, which may have been adapted from the French Rivière des Moines, literally meaning "River of the Monks". The city is a major center for the insurance industry and also has a sizable financial services and publishing business base. In fact, Des Moines was credited with the "number one spot for U.S. insurance companies" in a Business Wire article. The city is the headquarters for the Principal Financial Group, the Meredith Corporation, Ruan Transportation, EMC Insurance Companies, and Wellmark Blue Cross Blue Shield.