In 64BC, the Roman general Pompey added Lebanon, along with neighbouring Syria, to the Roman Empire. Lebanon flourished under Roman rule and saw an explosion in economic and intellectual activities. The inhabitants of the major cities such as Tyre, Byblos and Sidon were all granted Roman citizenship. These cities became centres for pottery and glass production as well as for the creation of the purple dye that the Phoenicians had been so famous for. Warehouses were created at the coastal harbours in order to store goods imported from elsewhere in the Empire and as far away as India. Trade flourished and Lebanon became a major exporter of Cedar, perfume and wine to Rome as well as fruit and wheat grown in the fertile valleys inland.
The economic prosperity which came with this establishment of Lebanon as a major centre of trade led to an increase in construction and urban development. The first ever Law School was built in what is present day Beirut and a substantial infrastructure of paved roads was built throughout the country so as to link the major cities with one another. Roman temples and monuments were built throughout Lebanon and their ruins punctuate the countryside in the present day with one of the largest to be found at Baalbek.
After the death of Theodosius in 395AD, the Roman Empire was divided into two: the Byzantine (Eastern) part with its capital at Constantinople and the Western part with Rome at its centre. As part of the Byzantine Empire, Lebanon continued to flourish and develop for a further century until earthquakes in the 6th century destroyed Beirut and the Baalbek temple complex, killing up to 30,000 people. The Law school was also destroyed. This natural disaster, together with corruption and religious unrest which was prevalent in the Byzantine Empire at that time, led to disorder and confusion and weakened the empire leaving it vulnerable to invasion. By this time, the majority of the population of Lebanon had converted to Christianity in common with the rest of the Byzantine Empire but by 636AD Lebanon was occupied by the newly converted Muslim Arabs from the Arabian Peninsula.