Among the men that the valley and its resources made famously wealthy were: Andrew Carnegie, Andrew Mellon, Henry Clay Frick, Henry Heinz, George Westinghouse, and Charles Schwab. Along with great wealth also came great waves of immigration into the area from Southern, Central and Eastern Europe as well as the great poverty of the non-unionized workers. In 1891 American labor peace was broken with the uprising of steel workers in Homestead, Pennsylvania. For days the city and its massive steel mill were taken over by the workers, repelling attacks by a small army of Henry Clay Frick (U.S. Steel) hired Pinkertons and local law enforcement until finally the issue was resolved by what would become the Pennsylvania National Guard.