See Donat. Roma Antiqua,1. iii. c. 14,1. iv. c. 12; and the learned, though confused, Dissertation of Bargaeus on Obelisks, inserted in the fourth volume of Graevius's Roman Antiquities, p. 1897-1936. This dissertation is dedicated to Pope Sixtus V., who erected the obelisk of Constantius in the square before the patriarchal church of St. John Lateran.