Perpugilliam “Peri” Brown (born 1966) was an American college student who accidentally joined the Fifth Doctor during his visit to Lanzarote. She then elected to remain with him for the rest of her vacation time. She remained with the Doctor after his regeneration into the Sixth Doctor, but found it harder to get along with him because of his now brash and arrogant persona.
Peri was separated from him by the Time Lords so that they could cover up the Ravolox conspiracy. According to the Master, Peri was wed to King Yrcanos, but that was just part of the truth. As it turned out, there were several future versions of Peri’s life due to interventions of various Time Lord factions. One of these versions of Peri eventually rejoined the Sixth Doctor on his travels.
Her unusual name meant, according to her, “she who lives in the hills.” (AUDIO: The Bride of Peladon)