The Gray Wolves were corrupt Chicago aldermen who held office from the 1890s to the 1930s.
[1] The Chicago City Council frequently gave franchises to private businesses to maintain public services.
Many businesses bribed the aldermen to be awarded such contracts, a practice known as "boodling".
This and similar schemes resulted in the formation of the Municipal Voters League in 1896 to throw the Gray Wolves aldermen off the council.
[1] Lincoln Steffens, a muck-raking reporter from McClure's Magazine, was the first to describe these aldermen as gray wolves "for the color of their hair and the rapacious cunning and greed of their natures.