At which battle did Julius Caesar achieve victory over Pompey?

Julius Caesar achieved a significant victory over Pompey at the Battle of Pharsalus, which took place in 48 BCE during the Roman Civil War. This battle was pivotal in determining the direction of Roman leadership, as Caesar's forces, though outnumbered, employed superior tactics and strategies that ultimately led to a decisive defeat for Pompey.

The tactics employed by Caesar included the strategic use of his infantry to create openings in the enemy formations. Additionally, he capitalized on Pompey's poor decision-making, which included an overly cautious approach during the battle. This victory effectively turned the tide of the civil war in favor of Caesar and solidified his position as the pre-eminent leader in Rome.

The other battles listed do not relate to Caesar's conflicts with Pompey. The Battle of the Somme was a significant World War I engagement, the Battle of Brandywine was an American Revolutionary War battle between British and American forces, and the Battle of Lake Erie was a key naval engagement during the War of 1812. Each of these events occurred in different historical contexts and involved different sets of leaders and military strategies, highlighting the importance of focusing on the specific historical context relevant to Caesar's campaign against Pompey.