Obelisks belong to the oldest and most simple monuments of Egyptian architecture, and are high four-sided pillars, diminishing as they ascend, and terminating in a small pyramid. Herodotus speaks of them, and Pliny gives a particular account of them. The latter mentions king Mesphres, or Mestres, of Thebes, as the first builder of obelisks, but does not give the time; nor is this king noticed either by Herodotus or Diodorus. It is probable that these monuments were first built before the time of Moses, at least two centuries before the Trojan war. There are still several obelisks in Egypt; there is one erect, and another fallen at Alexandria, between the new city and the light-house; one at Matarea, among the ruins of old Heliopolis; one in the territory of Fayoum, near ancient Arsinoë; eight or ten among the ruins of Thebes; the two finest at Luxor, at the entrance of the temple, &c. These obelisks, exclusively of the pedestals, are mostly from 50 to 100 feet high, and of a red polished granite (sienite); a few of the later ones are of white marble and other kinds of stone. At their base, they commonly occupy a space of from 4½ to 12 feet square, and often more. Some are adorned on all sides, and some on fewer, with hieroglyphics cut in them, sometimes to the depth of two inches, divided into little squares and sections, and filled with paint: sometimes they are striped with various colors. Some are entirely plain and without hieroglyphics. The foot of the obelisk stands upon a quadrangular base, commonly two or three feet broader than the obelisk, with a socket, in which it rests. They were commonly hewn out of a single stone, in the quarries of Upper Egypt, and brought on canals, fed by the Nile, to the place of their erection.

The Romans carried many of them from Egypt to Rome, Arles, and Constantinople, most of which were afterwards overturned, but have been put together and replaced in modern times. Augustus, for instance, had two large obelisks brought from Heliopolis to Rome, one of which he placed in the Campus Martius. The other stood upon the Spina, in the Circus Maximus, and is said to have been the same which king Semneserteus (according to Pliny) erected. At the sack of Rome by the barbarians, it was thrown down, and remained, broken in three pieces, amidst the rubbish, until, in 1589, Sixtus V. had it restored by the architect Domenico Fontana, and placed near the church Madonna del Popolo. Under Caligula, another large obelisk was brought from Heliopolis to Rome, and placed in the Circus Vaticanus. It has stood, since 1586, before St. Peter's church: it is without hieroglyphics; and, with the cross and pedestal, measures 126 feet in height. It is the only one in Rome which has remained entire. Its weight is estimated at 10,000 cwt. Claudius had two obelisks brought from Egypt, which stood before the entrance of the Mausoleum of Augustus, and one of which was restored in 1567, and placed near the church of Santa Maria Maggiore. Caracalla also procured an Egyptian obelisk for his circus, and for the Appian Way. The largest obelisk (probably erected by Rameses) was placed by Constantius II., in the Circus Maximus at Rome. In the fifth century, it was thrown down by the barbarians, and lay in pieces upon the ground, until Sixtus V., in 1588, had it raised upon the square, before St. John's church of the Lateran, thence called the Lateran obelisk. It is beautifully adorned with sculpture; its weight is 13,000 cwt.; its height, exclusive of the pedestal, 140 feet; with the pedestal, 179 feet. Several others have been erected by succeeding popes.