Who was the Roman emperor when Jesus was born?

At the time of Jesus' birth, Caesar (Octavian) Augustus was the Roman Emperor. Augustus ruled from 27 BC until his death in 14 AD. During his reign, Augustus established a new basis for Roman government.

This new system of government stood for three centuries. Under this system, known as the Principate, a series of rulers presided over the longest period of unity, peace and prosperity that Western Europe, the Middle East and the North African seaboard have experienced in their recorded history. One of the most significant additions to his empire, according to antipas.net, was a 50,000 mile roadway that included bridges.