 The regions that comprise today's Iran and Pakistan have been under the rule of contiguous Eurasian polities at various points in history, as Pakistan straddles an intermediary zone between the Iranian Plateau and Indian subcontinent.The Persian Achaemenid Empire, which spanned (among other regions) the area between the Balkans and the area of the Indus River (known to the Persians as "Hind" ) at its height, conquered the regions comprising modern-day Balochistan, Sindh, Khyber Pakhtunkhwa and Western Punjab during the reign of Darius I.Imperial Iran maintained close relations with Pakistan during the Cold War, partly owing to their mutual alliance with the United States-led Western Bloc.