The Persians were an ancient human civilisation. A peri was a creature from their mythology which the Sixth Doctor referenced to his companion Peri. (TV: The Twin Dilemma)
Pythagoras learned from Persian magi in Babylon. (PROSE: The Pythagoras Problem)
Having saved Alexander the Great from androids, Time Agents Jack Harkness and John Hart claimed that the assassins were Persians. (AUDIO: The Death of Captain Jack)