Students at the elite Episcopal High School in Alexandria are asked to live by a simple code — don’t lie, don’t cheat, don’t steal and report your classmate who does.

“That fourth point is the kicker, of course,” said F. Robertson Hershey, headmaster at Episcopal. School historians say the campus is home to one of the oldest honor codes in the nation, instituted around 1870, and one of the few remaining schools that demand responsibility for classmates.