Incorporated as the City of Fort Wayne on February 22, 1840, the city prospered under the launch of the Wabash and Erie Canal. Fort Wayne's nickname, The Summit City, was coined due to its location at the zenith of the locks on the canal. The city lost national prominence in the demise of the Wabash and Erie Canal as the railroad system quickly took its place. Population growth occurred most in the 19th century, with the arrival of German, Polish, and Irish immigrants, bringing large numbers of Roman Catholics and Lutherans. Fort Wayne is also informally referred to as the City of Churches.