Frontier policies and inter-state relations

Medieval Indian states were defined as much by their frontiers as by their capitals, because border zones controlled mountain passes, river crossings, and trade routes, and because they were home to chiefs who could switch allegiance. Sultanate and Mughal frontier policy therefore mixed forts, garrisons, marriage alliances, and tributary arrangements rather than relying on fixed borders. A concrete example is Akbar's handling of the north-west frontier, where Rajput alliances, forts, and campaigns towards Kabul and Kandahar guarded the route into India. Studying frontiers also explains why relations between neighbouring states swung between war, diplomacy, and uneasy coexistence.