Some people believe Julius Caesar was the first emperor of Rome, but this isn't so. He was named dictator for life by the senate (who really didn't have any choice, what with Caesar's army at their throat), but he was not the true founder of the empire. He was assassinated and another period of civil war followed, after which the victor Octavian became the first real Emperor.

Octavian had been adopted by his uncle who we know as Julius Caesar (his familiar name was Gaius), and took the family name Caeser after the dictators murder. After Octavian's victory over his chief rival Marcus Antony, the senate named him Augustus as well. In future, all emperors would take Ceaser or Augustus as part of their official name, and over two centuries they evolved into titles.

The denarius was the $100 bill of its day, a silver coin about the size of a dime and about a quarter heavier. It was worth 4 sestertii, 8 dupondii (a brass coin), 16 asses, or 64 quadrans (a small bronze coin). But it took 25 denarii to buy a single gold aureus, which were struck at 50 to the Roman pound at the time, I think.

The portrait of Augustus is probably recognizable. It is certainly idealized. It can be seen to resemble conventional portraits of Alexander the Great at the time (though whether *they* were accurate at all is a moot point). Around the edge of the obverse side is the name Caesar Augustus, the flattering title "divine" (most emperors had to die before earning this), Felix (happy), Pater Patrriae (father of his country). On the reverse is shown his two sons, Caius & Lucius. They were to be his heirs, but unfortunately they pre-deceased their father. In the end, Augustus was forced to adopt as his successor his son-in-law by his second wife, Tiberius.

It was under Tiberius's troubled watch that Jesus was crucified, so it was to Tiberius one was to render unto Ceasar that which was Caesar's.