At the beginning of the nineteenth century nomads held considerable power in Iran and the Ottoman Empire. In Ottoman lands, westernizing reforms in landholding and local administration undermined tribal power and led to increasing sedentarization. In Iran, tribes and nomads remained central to the military, and retained power through World War I. In both states, the government controlled nomads by incorporating tribal leadership into government structure. New concepts of nationalism portrayed nomads as backwards and alien. World War I and the Constitutional Revolution of Iran brought an upsurge of nomad activity, but from the 1930s the Mandate powers, the Turkish Republic, and the Pahlavi dynasty of Iran worked actively to suppress nomadism. Even more important was the revolution in transportation and weaponry. The steamship, telegraph and railway replaced many caravan routes, destroying the market for camels. The machine gun and airplane made cavalry obsolete, while the truck ended the usefulness of caravans and the need for nomad guards over trade routes. Thus, nomads lost much of their usefulness to the state.