The Great Game was a rivalry between the 19th-century British and Russian empires over influence in Central Asia, primarily in Afghanistan, Persia, and Tibet. The colonial empire and great land power (heartland state) used military interventions and diplomatic negotiations to acquire and redefine territories in Central and South Asia. Russia conquered Turkestan, and Britain expanded and set the borders of British India. By the early 20th century, a line of independent states, tribes, and monarchies from the shore of the Caspian Sea to the Eastern Himalayas were made into protectorates and territories of the two empires.
Though the Great Game was marked by distrust, diplomatic intrigue, and regional wars, it never erupted into a full-scale war directly between Russian and British colonial forces. However, the two nations battled in the Crimean War from 1853 to 1856, which affected the Great Game. The Russian and British Empires also cooperated numerous times during the Great Game, including many treaties and the Afghan Boundary Commission.