The city was founded ex nihilo as a military colony by the emperor Trajan around 100 CE. It was intended to serve primarily as a Roman bastion against the Berbers in the nearby Aures Mountains. It was originally populated largely by Roman veterans and had expanded to over 10,000 residents of Roman people, and even African colonists from other parts of the Roman Empire.[citation needed] Although most of them had never seen Rome before, and Timgad was hundreds of miles away from the Italian city, Trajan invested heavily in Roman culture and identity.[1]

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. During the Christian period, Timgad was a diocese which became renowned at the end of the 4th century when Bishop Optat became the spokesman for the Donatist movement. After Optat, Thamugadai had two bishops Gaudentius (Donatist) and Faustinus (Catholic).[2]

In the 5th century, the city was sacked by the Vandals before falling into decline. Timgad was destroyed at the end of the 5th century by Berber tribes from the Aurès Mountains. In 535 CE, the Byzantine general Solomon found the city empty when he came to occupy it during the Vandalic War. The Byzantine Reconquest revived some activities in the city, defended by a fortress built to the south, in 539, reusing blocks removed from Roman monuments. In the following century, the city was briefly repopulated as a primarily Christian city.

The Arab invasion brought about the final ruin of Thamugadi and it ceased to be inhabited after the 8th century CE.[3] Because no new settlements were founded on the site after the 7th century CE, the city was partially preserved under ground up to a depth of approximately one meter.

Travelling Northern Africa, British explorer James Bruce reached the city ruins on 12 December 1765, likely being the first European to visit the site in centuries and described the city as “a small town, but full of elegant buildings.” In 1790, he published the book Travels to Discover the Source of the Nile, where he described what he had found in Timgad. The book was met with skepticism in Great Britain, until 1875 when Robert Lambert Playfair, Britain's consul in Algiers, inspired by Bruce's account, visited the site. In 1877 Playfair described Timgad in more detail in his book Travels in the Footsteps of Bruce in Algeria and Tunis. According to Playfair, “These hills are covered with countless numbers of the most interesting mega-lithic remains”.[4] The French colonists took control of the site in 1881, began investigations and maintained it until 1960. During this period, the site was systematically excavated.[5]

 

Panorama of Timgad ruins