As states and empires increased in size and contacts between regions multiplied, religious and cultural systems were transformed. Religions and belief systems provided a bond among the people and an ethical code to live by. These shared beliefs also influenced and reinforced political, economic and occupational stratification. Religious and political authority often merged as rulers (some of whom were considered divine) used religion, along with military and legal structures, to justify their rule and ensure its continuation. Religions and belief systems could also generate conflict, partly because beliefs and practices varied greatly within and among societies.