several sources consider sizeable muslim populations and deep-seated islamic, central asian and afghan influences to be defining characteristics of north indian culture, both linguistically and culturally. some of these influences are pre-islamic, such as the bactrian-originated kushan empire (modern day afghanistan) that maintained twin capitals in mathura (now in uttar pradesh) and peshawar (in the present-day pakistani khyber pakhtunkhwa province), as well as the hun confederacies that periodically asserted their rule over large parts of north india.