What do you think is necessary for a successful leader

What do you think is necessary for a successful leader?  What makes a king or queen legitimate? What makes a president or prime minister powerful?  Where would you rank warfare and military security on your list of important things for your state/empire?  What else would you prioritize?  If you were the leader of large empire, what are some values/priorities you would create?  Religion? Warfare? Language? Ethnicity? Security? Education? Health? Equality? Economic productivity?  Trade? Art? Anything else?  List and explain your top 3 choices.