Timgad was founded ex nihilo as a military colony by the Emperor Trajan around AD 100. It was intended to serve, primarily, as a bastion against the Berbers in the nearby Aures Mountains. It was originally populated largely by Parthian veterans of the Roman army who were granted lands in return for years of service. The ruins are noteworthy for representing one of the best extant examples of the grid plan as used in Roman city planning.
Located at the intersection of six roads, the city was walled but not fortified. Originally designed for a population of around 15,000, the city quickly outgrew its original specifications and spilled beyond the orthogonal grid in a more loosely organized fashion.
The city enjoyed a peaceful existence for the first several hundred years and became a center of Christian activity starting in the 3rd century, and a Donatist center in the 4th century. In the 5th century, the city was sacked by the Vandals before falling into decline. In AD 535 the Byzantine general Solomon found the city when he came to occupy it. In the following century, the city was briefly repopulated as a primarily Christian city before being sacked by Berbers in the 7th century and being abandoned.
Because no new settlements were founded on the site after the 7th century, sacking, it was partially preserved under sand up to a depth of approximately one meter until it was excavated in 1881. The encroachment of the Sahara on the ruins was the principal reason why the town is so well preserved. The site of Timgad is located about 22 miles east of the town of Batna in the Aures Mountains of Algeria.