Crossing the Rubicon

On 10 January 49 BC, leading one legion, the Legio XIII Gemina, General Julius Caesar crossed the Rubicon River, the boundary between the Cisalpine Gaul province to the north and Italy proper to the south, a legally proscribed action forbidden to any army-leading general. The proscription protected the Roman Republic from a coup d'état; thus, Caesar's military action began a civil war.

This act of war on the Roman RepublicThe Roman Republic was a form of government of Rome and the era of the classical Roman civilization when it was run through public representation of the Roman people. Beginning with the overthrow of the Roman Kingdom (traditionally dated to 509 BC) and ending in 27 BC with the establishment of the Roman Empire, Rome's control rapidly expanded during this period - from the city's immediate surroundings to hegemony over the entire Mediterranean world.Roman Republic by CaesarJulius Caesar (100-44 BC), was a Roman politician and general who played a critical role in the events that led to the demise of the Roman Republic and the rise of the Roman Empire. Caesar is considered by many historians to be one of the greatest military commanders in history. Julius Caesar »Caesar led to widespread approval amongst the Roman civilians, who regarded him as a hero. The historical records differ about which decisive comment Caesar made on crossing the Rubicon: one report is Alea iacta est (usually translated as "The die is cast").

• Outline of the Great Roman Civil War (49–45 BC)
  

  HISTORIC BATTLES

  Great Roman Civil War (49–45 BC)

  The Great Roman Civil War (49–45 BC), also known as Caesar's Civil War, was one of the last politico-military conflicts in the Roman Republic before the establishment of the Roman Empire. It began as a series of political and military confrontations, between Julius Caesar (100–44 BC), his political supporters, and his legions, against the Optimates (or Boni), the politically conservative and socially traditionalist faction of the Roman Senate, who were supported by Pompey (106–48 BC) and his legions. View Historic Battle »

  Pre-war politico–military situation: Caesar's Civil War resulted from the long political subversion of the Roman Government's institutions, begun with the career of Tiberius Gracchus, continuing with the Marian reforms of the legions, the bloody dictatorship of Lucius Cornelius Sulla, and completed by the First Triumvirate over Rome.

  Crossing the Rubicon: On 10 January 49 BC, leading one legion, the Legio XIII Gemina, General Julius Caesar crossed the Rubicon River, the boundary between the Cisalpine Gaul province to the north and Italy proper to the south, a legally proscribed action forbidden to any army-leading general.

  March on Rome and the early Hispanian campaign: Caesar's march on Rome was a triumphal progress. The Senate, not knowing that Caesar possessed only a single legion, feared the worst and supported Pompey.

  Greek, Illyrian and African campaigns: A major reason for Pompey's defeat was a miscommunication among front cavalry horsemen.

  Egyptian dynastic struggle: Pompey fled to Egypt, where he was murdered by an officer of King Ptolemy XIII.

  War against Pharnaces: After this show of strength against the Romans, Pharnaces drew back to suppress revolt in his new conquests.

  Later campaign in Africa and the war on Cato: While Caesar had been in Egypt installing Cleopatra as Queen, four of his veteran legions encamped outside of Rome under the command of Mark Antony.

  Second Hispanian campaign and the end of the war: Caesar gave chase and defeated the last remnants of opposition in the Battle of Munda in March 45 BC.

  Aftermath: Caesar was later proclaimed dictator first for ten years and then in perpetuity.

RESOURCES
This article uses material from the Wikipedia article "Caesar's Civil War", which is released under the Creative Commons Attribution-Share-Alike License 3.0.