Sardinian ruler, Salusio, the judge of Cagliari, was killed in the fighting and the organised resistance broke down. His troops may have met up with garrisons that had remained on the island after the failed expedition of 1015. He also established a beachhead at Luni, on the coast between Genoa and Pisa, according to the eleventh-century German chronicler and bishop Thietmar of Merseburg (Thitmarus), who mis-dates the event to 1015. Luni was reportedly taken by surprise, but the citizens and the bishop managed to flee. Both town and countryside were pillaged without resistance. To solidify his conquest, Mujāhid immediately set about building cities using the local Sards for slave labour (he may have had some buried alive in the walls of his new city). The area he controlled, the plain between the central mountains and the sea, corresponded roughly to the Judicature of Cagliari (regnum Calaritanum in the Liber, III, 45), whose judge he had defeated and killed. The site of one Islamic fortification can be approximated, for a Greek charter of 1081 makes reference to a "castro de Mugete" (castle of Mujāhid) near Cagliari, the chief city and port of the judicature. Archaeological research in the 1970s uncovered what may be Roman baths modified to fit Islamic tastes near Quartucciu. It is also possible that an Arab population had been present on the island for some time if it had indeed served as the staging area for the assault on Rome in 841. Medieval cartographers called the southeastern Sardinian coast from Arbatax south Sarabus, a corruption of the Sard for "the Arabs", and the very name "Arbatax" may derive from ārbaʿa, meaning "four", a possible reference to the four Byzantine forts which lined that section of the coast. The liberus de paniliu, a designation for the "semi-free Christian children of Muslim slaves", appear in several eleventh-century donation charters from the region. Religious diversity, owing to a large endemic Arab population, may also explain the slowness with which monasticism of either the Western or Eastern variety encroached upon the area. Second Christian expedition (1016) The presence of Ilario Cao, a Cardinal from Sardinia, in the curia of Pope Benedict VIII—"a warlike pope, who has been compared to Julius II ... [b]ut his role in the conflict with [Mujāhid] ... elevates him to a higher plane"—was probably instrumental in obtaining papal approval and even active support of a military venture to