My bank recently promoted me to a management role. How do I cope with leading a team that used to be my peers?

A promotion should be a great moment in your career; a bigger title, a bigger pay cheque, more responsibility, and maybe even a bigger office. But what happens when suddenly you become the leader of a team of former peers? How do you deal with the challenges and frustrations that divided loyalties, a shift in team dynamics, and your own uncertainty on how to handle conflict with friends? Is this the way it has to be or is there a way to gain control and be more effective?