By gathering information about the history of both. Social conditions, political subdivisions, The behaviour of the operating authority among them and other primary documents. Secondary and tertiary
By gathering information about the history of the peoples on both the social, political domination. Behavioral practices of authority among them, and more. Both documents are primary, secondary and tertiary.
By collecting data about the history of the two conditions, social political power politics. Practice of authority among them behavior and so on. Both documented primary secondary and tertiary care.