Solar Eclipse of 50 BC, Before Julius Caesar crosses the Rubicon River
Note this eclipse was seen by Julius Caesar as the Roman Governor of Gaul and in Rome by Pompey the Great and the Senate. The solar eclipse may have raised fears on the part of the Roman Senate that Caesar wanted more than just a consular position. Nonetheless in 50 BC the senate wanted Julius Caesar to disband his army and return to Rome. In January of 49 BC, Julius Caesar and his army crossed the Rubicon River starting the rebellion that began Roman Empire.
The coin above was minted in 44 BC at Rome just before the assassination of Julius Caesar. The crescent is likely solar to the left of his portrait. It represents the solar eclipse of 50 BC. This solar eclipse was minted to represent the divine authority with which Caesar took over Rome. Shortly after his assassination the crescent was replaced with a comet tail to symbolize Caesar going to the heavens. The comet of Julius Caesar was also commemorated on the coins of Caesar Augustus to represent his divine authority over the Empire.
Photo Sergey Nechayev Ancient Coins