In what is now Algeria, an empire began around 200 BC, stretching all the way to the River Mulucha. In the early years it was mostly just a slew of different nomadic tribes and bands. The Eastern part was known as Massylii and the Western side was Masaesyli. It was not a cohesive, unified civilization until the Second Punic War (218-206 BC) that Massylii king Massinissa deafeated Syphax of the Masaesyli region.
During this time, the Romans fought the Carthagians largely over control of a Iberian coastal city. This meant that since the Massylii were allies to the Romans, and the Masaesyli had ties with Carthage (Syphax was married to the daughter of a Carthagian commander named Hasdrubal), that Massylii were able to conquer their Western neighbors.
Massinissa and his men contributed greatly to the Roman victory lending their expert horsemanship and clever cavalry tactics. Syphax would be exiled to Tibur, where he would die.
Massinissa ruled the Numidians for nearly fifty years with the support of the Roman Empire behind him. He wanted Numidian pastoral people to become peasant farmers, and help make Numidia a agrarian society. Also during this time, he overtook a great amount of further Carthagian territory, and was one of the most powerful men in North Africa. He died in 148 BC, and at this time his empire extended all the way from Mauretania through former Carthagian territory Cyrenaica, an eastern coastal region of what is modern day Libya.
After his death, Numidia saw a number of different leaders, causing a divide among the civilization, which prompted Rome to split Numidia into two parts; West and East.
Later they would have wars with Rome, over their de facto hegemony of the place. Julius Caesar around 40 BC formed a new province known as Africa Nova out of some of the Numidians’ land, and Augustus united Africa Nova and Africa Vetus (old Africa), which was the area surrounding Carthage. A separate province of Numida would be created formally by emperor Septimius Severus. Rome’s Third Legion army took up permanent base at Lambessa. Increased security by the Romans, the Numidians economy flourished through two centuries.
By the third century Christianity spread very wildly, and Numidia became a center of a sect of the religion called Donatism. It was a religion which was fairly sizable. It’s inception grew out of the emperor Diocletian who persecuted and killed Christians throughout his reign. Donatists refused to accept sacrament from or recognize any priest, or person who had renounced Christianity during this fearful time.
The Catholics felt that someone could be absolved of such a sin through years of Penance, but the Donatists felt that anyone who had renounced the religion after having been baptized should not be allowed to hold any kind of post or have authority within the church. They also had problems with Emperor Constantine, and he presented a death penalty to all who “disturbed the peace of the kingdom”. They did not recognize Constantine as the holy figure he saw himself as.
Numidia, and Donatism would both wain in the centuries to come with attack from Vandals, the Arab Conquest and the gradual decline of Christianity in North Africa.
http://www.britannica.com/EBchecked/topic/422426/Numidia
http://www.britannica.com/EBchecked/topic/169009/Donatist