Upon the invitation of Catherine the Great, 25,000 Germans immigrated to the Volga valley of Russia to establish 104 German villages from 1764 to 1767. A century after the first Germans had settled in the Volga region, Russia passed legislation that revoked many of the privileges promised to them by Catherine the Great. The sentiment in Russia became decidedly anti-German. Russia first made changes to the German local government. In 1874, a new military law decreed that all male Russian subjects, when they reached the age of 20, were eligible to serve in the military for 6 years. For the German colonists, this law represented a breach of faith. In the 1880s the Russian government began a subtle attack on the German schools.