Emperor Trajan named the city in commemoration of his mother Marcia, eldest sister Ulpia Marciana, and father Marcus Ulpius Traianus.

[2] Thamugadi is the Berber name of the place where the city was built, to read Timgad plural form of Tamgut, meaning "peak" or "summit".

[3][4] Although most of them had never seen Rome before, and Timgad was hundreds of miles away from the Italian city, it invested heavily in Roman culture and identity.

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.

[7] However, the early Muslim conquests brought about the final ruin of Thamugadi as it ceased to be inhabited by the 8th century.

[8] Travelling Northern Africa, Scottish 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 Library at Timgad was a gift to the Roman people by Julius Quintianus Flavius Rogatianus at a cost of 400,000 sesterces.

[12] As no additional information about this benefactor has been unearthed, the precise date of the library's construction remains uncertain.

Based on the remaining archaeological evidence, it has been suggested by scholars that it dates from the late 3rd or possibly the 4th century.

[12] Oblong alcoves held wooden shelves along walls that would likely have been complete with sides, backs and doors, based on additional evidence found at the library at Ephesus.