Tebessa (2717 ft.; pop. 5700, mostly Mohammedans), a poor town, now unimportant except as the centre of the E. Algerian phosphate trade, was the ancient Theveste, one of the most prosperous towns in Inner Numidia from the Punic period (about B.C. 250–200) onwards. It was the first headquarters of the Third Legion (p. [286]); in 123 A. D. it was connected with Carthage by a Roman military road; and after its destruction by the Berbers it was re-founded in 535 by Solomon, the general of Justinian (p. [541]). Its ruins of the late-Roman and Vandal periods are among the finest in Barbary, but as they lie off the beaten track they are almost forgotten.
The town is still enclosed by the Byzantine Walls built by Solomon, forming a rectangle of 350 by 306 yds., with fourteen towers, two gates, and a sally-port on the S. side. The old upper gallery and the battlements were removed in 1852 when the walls were restored.
The modern W. Gate, the Porte de Constantine, leads first to the pleasant Place d’Armes, the centre of traffic. Two minutes’ walk to the E. of this is the so-called Porte de Solomon, the most interesting part of the fortifications, with a round-arched passage and two square towers 56 ft. high. Outside of it the natives hold market on Tuesdays and Wednesdays.
The N. Gate, where the walls project a little on both sides, is formed by the *Arch of Caracalla, dating from 214 A. D., once in the middle of the far more populous Roman town, but now at the end of the main street coming from the Place d’Armes.
This arch, resembling the Janus Quadrifrons at Rome, is the most imposing Roman monument of the kind in Algeria, rivalling those of Tripoli (p. [408]) and Leptis Magna (p. [412]). It forms a square of about 12 yds. each way, with four round-arched passages, 27 ft. high and 15 ft. wide. Each pillar is adorned on its two outer sides with two Corinthian pilasters and two projecting Corinthian columns, all on a common base. Of the sculptures on the keystones of the archways, under the lavishly decorated architrave, there are preserved, on the E. side, a medallion in high relief of Minerva and a Medusa, and on the W. side a Fortuna (goddess of the town) and an eagle holding a bundle of thunderbolts. On three sides, in the middle of the attica, which is 4 ft. high, there are Latin inscriptions referring to Caracalla and his parents, Septimius Severus and Julia Domna. On the N. side, when the arch was restored, there was added an inscription in honour of Solomon. On the S. side is still preserved an ædicula, one of the four destined for statues adjoining the central dome. On the inner side of two of the pillars are long inscriptions from the testament of C. Cornelius Egrilianus, the builder of the triumphal arch.
The highroad now descends to the N. to the (7 min.) so-called **Basilica, the most remarkable early-Christian ruin in Algeria, still in some respects an enigma to archæologists. Built mainly of Roman materials, and itself used for centuries as a quarry, it still forms an immense quadrilateral of about 213 by 88–115 yds., systematically excavated for the first time in 1888–92. The oldest parts of the edifice, perhaps of the late 4th cent., are believed to be the basilica and the memorial chapel; the main street, the court, and the ‘stable’ seem to belong to a second building period, perhaps also prior to the Vandal era. The monastery, with its fortifications, and the additions to the memorial chapel date probably from the Vandal period; the small ‘emergency chapel’ is perhaps a later Byzantine addition. The custodian (fee ½–1 fr.) is to be found at the little house near the E. gate.
The E. Gate, the old main entrance, once adorned externally, in the style of a Roman triumphal arch, with Corinthian pilasters and jutting columns, is in fair preservation. Thence ran the paved Main Street, 8 yds. wide, without wheel-ruts, past the Basilica on the right and the court and ‘stable’ on the left, to the W. Gate, the ancient subsidiary entrance.
From the N. side of the main street, formerly flanked with three colonnades, a flight of fourteen steps, 9½ ft. high in all, ascends to the portico of the Basilica, which was once preceded by eight columns. Three portals here opened into the Atrium, the square forecourt of the church, with remains of the Cantharus, or fountain of purification, in the centre. Near the entrance-wall are two side-rooms whence winding staircases ascended to the upper floor and the church galleries.
The Church, built of solid masonry, consisted of nave and two aisles, 50 by 24 yds. in all; but now nothing remains save the external wall of the left aisle, two arcades of the nave, and the choir-recess. The formation of the arcades, with low pillars and Corinthian columns in front, is peculiar. The site of the choirscreen and of the base of the altar is still traceable. Of the galleries, supposed to have been added on the occasion of a restoration of the church, there still lie fragments of the columns and imposts all around. The mosaic pavement is covered with earth.
From the front part of the right aisle twelve steps descend into an almost square outer building (25½ by 22 yds.), contemporaneous with the church. The middle of this is occupied by the Trichorum, a trefoil-shaped hall, with three rounded apses, probably a Memorial Chapel, resembling the early-Christian cemetery-chapels, and dedicated to some martyr or bishop buried under the altar. The four corner-rooms served as Tomb Chambers.