The sources for pre-Arab trans-Saharan contacts are poor, but at least for the central Sahara a picture can be made out. The alignment of rock paintings and engravings of chariots along two trans-Saharan routes has been supposed to prove regular traffic across the desert. The inference is unjustified, but literary and archaeological sources indicate that the conclusion is correct. Herodotus attests the use of a route running west from Egypt to the Fezzan, then apparently south-west via Tassili and Hoggar to the Niger. This corresponds with the central Saharan 'chariot-route'. There was also a route to the Garamantes of the Fezzan from the Punic settlements on the coast of Tripolitania. Carthage imported from the Garamantes the precious stones known as 'carbuncles', which were apparently brought to the Fezzan from the south-west. Other possible imports are slaves and gold. Carthage imported gold from West Africa by sea, and it seems likely that her explorations down the coast were inspired by an overland trade in gold. But there is no direct evidence for such a trade. In the second century B.C. Rome replaced Carthage in control of the coast of Tripolitania. Between 20 B.C. and A.D. 86 she fought a series of wars with the Garamantes. Later friendly relations were established, but further trouble led to the organization of the 'limes Tripolitanus' after A.D. 201. Trade is attested by imported Roman material in tombs of the Fezzan dating from the late first to the fourth centuries. There is evidence that the Romans imported ivory from the Garamantes, and slaves are now attested directly. The commodities exported north by the Garamantes came not from the Fezzan, but from farther south. Literary sources refer to hunting expeditions and raids to the south, and finds of Roman material have been made along the 'chariot-route' south-west of the Fezzan as far as Ti-m-Missao. Trade ended with the collapse of Roman rule in North Africa. It was revived with the Byzantine reconquest after A.D. 533, and Christianity penetrated to the Fezzan. In 666 the Arabs overran the Fezzan.