Imperialism refers to a policy or practice by which a powerful state extends its political, economic, military, and cultural influence over weaker countries or territories. It may involve direct territorial conquest and colonial rule, or indirect control through economic pressure, diplomacy, military intervention, and political influence. Although imperial practices existed in ancient and medieval times, modern imperialism became particularly significant from the nineteenth century, when European powers expanded their control over large parts of Asia, Africa, and other regions. The economic explanation of imperialism emphasizes the interests of capitalism and industrial development. According to Marxist thinkers, the growth of industrial capitalism created a need for new markets, raw materials, investment opportunities, and profitable areas for surplus capital. Vladimir Lenin, in particular, described imperialism as the highest stage of capitalism. He argued that the concentration of capital led to the growth of monopolies and finance capital, which encouraged capitalist states to compete for colonies and economic territories. In this interpretation, imperialism was closely connected with capitalist competition and the search for greater profits. J. A. Hobson offered another important economic explanation.