Chemical and petrographic studies of the two Colossi of Memnon located near Luxor, and of Egyptian quartzite quarries, indicate that the rear pedestal blocks of the northern statue were quarried at Aswan, while the other components of the monuments were quarried near Cairo. The rear blocks of the northem statue were probably part of the reconstruction project undertaken by Septimius Severus. The tilting of the statues suggests that the rear part of the lower torso of the northern statue was moved when the statue was reconstructed. Part of the present-day tilting of the northem statue probably occurred prior to the reconstruction. See also AATA 11-294.