All eyes were on the prom queen, who was being crowned in front of these Princeton seniors and their dates at the 1950 senior class “Promenade,” ­according to archivists. A longstanding campus tradition, the senior prom was held for many years in Dillon Gym but now takes place in Jadwin the night before Commencement. Other changes: Seniors bring family and friends, and formal attire is not required. Can any 1950 graduates name the prom queen and her escort?