Industrial relations at the beginning of the 20th century were especially volatile as industry leaders pitted themselves against labor unions. Socialism and communism became more prevalent ideologies especially in Europe and Russia.  Many immigrants to the United States from southern Europe and Wales were attracted to these movements that supported the laborers who worked in especially harsh conditions in the factories and mines. In the mines of Colorado the highest number of workers were English (including many Welsh), Italians, Slavs, Greeks and Austrians. Many other Europeans as well as Mexicans and Japanese also worked the mines. The labor unions represented these people and gave them a unified face to counter the power of big businesses. Labor unions also supported one another to provide a larger labor base. The correspondence below illustrates the solidarity of the labor movement at the time and also documents issues that led up to the "Ludlow Massacre. "