Some allies of the Romans in Gaul (modern France and Belgium) were defeated by Germanic tribes. This was used by Caesar as a pretext to intervene into Gaul and to begin its conquest. Caesar was to prove to be a general of genius.<ref>Grant, p. 98</ref> He defeated the Germanic tribes with great brutality. The Gaul in the North and West were alarmed by the appearance of Romans and they began to form defensive alliances. These were interpreted by Caesar as a threat to the Romans even though this may not have been the case. He ordered his legions to march to the far north of Gaul and he conquered much of the area and later he also extended Roman influence into to the south-west. Caesar had begun the conquest of Gaul without the sanction of the Senate and many regarded his campaign as an illegal war. At a conference in Lucca in 55 BCE at this Caesar was able to extend his consulship, and his command in Gaul for another five years.
However, many fierce tribes such as the Belgae continued to resist Romans and Caesar was involved in much fierce fighting. He did find the time to launch a raid on Britain. The Roman general was a great propagandist and he wrote reports on his campaigns that informed the public of his achievements. These are considered to be classics of Latin Literature. While Caesar was popular with many , he was hated by many Senators in Rome. He continued his campaigns and at the Battle of Alessia he won a decisive victory, which that ended the conflict. After his victory, Caesar had the command of a large army of seasoned troops who were loyal to him and many partisans in his native city. Much of the wealth he made in Gaul was used to finance his supporters. Caesar had by now even eclipsed Pompey. However, the Senate wanted to strip him of his army and to prosecute him. This led him to demand that he be allowed to retain control of his legions . He needed them to protect his interests when . When this was refused , Caesar crossed the Rubicon and occupied Rome. While it was an aggressive step to take, which he saw Caesar justified it as an act of self-defence against those who would harm him and his supporters.<ref> Plutarch, ix</ref>
==== Civil Wars (49-44 BCE)====