The rectangular Great Court to its west covers around and included the main altar for burnt offering, with mosaic-floored lustration basins to its north and south, a subterranean chamber, and three underground passageways wide by high, two of which run east and west and the third connecting them north and south, all bearing inscriptions suggesting their occupation by Roman soldiers. These were surrounded by Corinthian porticoes, one of which was never completed. The columns' bases and capitals were of limestone; the shafts were monoliths of highly polished red Egyptian granite high. Six remain standing, out of an original 128. Inscriptions attest that the court was once adorned by portraits of Marcus Aurelius's daughter Sabina, Septimius Severus, Gordian, and Velius Rufus, dedicated by the city's Roman colonists. The entablature was richly decorated but is now mostly ruined. A westward-facing basilica was constructed over the altar during the reign of Theodosius; it was later altered to make it eastward-facing like most Christian churches.