In a series of quite brilliant campaigns, Julius added a considerable amount of territory to the Roman Empire in northern France, Belgium, and even southern Great Britain, subjugating the Celts in all these territories. After the campaign, the Senate declared Julius an enemy of the state and demanded that he hand over his generalship and province. Julius, however, ordered his troops to cross the river Rubicon, which separated his province from Italy, thus committing a grave crime against the state. Civil war was fought between the two great generals, Pompey and Caesar; but in 48 BC Caesar defeated Pompey at Pharsalus in Greece. Caesar then turned his forces towards Asia Minor in a conquest so swift that Caesar described it in three words: "Veni, vidi, vici" ("I came, I saw, I conquered"). Caesar returned to Rome in 46 BC and had the Senate appoint him Dictator. He was given imperium over the Roman Empire and was, for all practical purposes, above the law and the constitution. The Romans, proud of their Republican tradition, deeply resented his power, and on 15th March 44 BC, a group of conspirators, led by Gaius Cassius Longinus and Marcus Junius Brutus, assassinated Caesar as he entered the Senate.

Main Roman Coin Book and Other References:

RIC = Mattingly, Harold    The Roman Imperial Coinage
BMC = Coins of the Roman Empire in the British Museum
RSC = Seaby, H A    Roman Silver Coinage
RCV = Sear, David R    Roman Coins and Their Values
Cr = Crawford, Michael    The Roman Republican Coinage
SB = Sear, David R    Byzantine Coins and Their Values
S = Coins of England and the United Kingdom
WW = Wildwinds.com (reference & attribution site)