Princess who helped Theseus escape the Minotaur (7)
I believe the answer is:
ariadne
(Other definitions for ariadne that I've seen before include "Aider of Theseus against the Minotaur" , "heroine of labyrinth" , "Successful at stringing lover along" , "subject of opera" , "She helped Theseus escape from the Minotaur's labyrinth" .)