Astrolabus stole some star charts from Voyager by travelling to Antarctica and threatening the Sixth Doctor with a gun so that he handed them over. Astrolabus fled, with the Doctor giving chase. Returning to his TARDIS, which was in the form of a lighthouse, Astrolabus told the Doctor how he had helped Alexandria develop into a crossroads for aliens. The city grew great under him and he helped build the world's first lighthouse there. A book known as the Insidium of Astrolabus was among the evil or arcane works which were kept in the Master's TARDIS library. (PROSE: The Quantum Archangel)