October, 43 B.C.
Caesar returned from Spain after defeating the forces of "Magnus" Gnaeus Pompeius (the Great Pompey) and his sons. Pompey was born in 106 B.C. And he made a great name for himself as a general at a very early age, largely because he had a talent for being "on the right side, in the right place, at the right time."
"He won important victories in Spain, for instance, in 77 B.C. against a revbellious Roman general, largely because that general happened to be assassinated at the crucial moment."
"In 61 B.C., he returned to Rome and at the age of forty-five received the most magnificent triumph Rome had seen up to that time. It is presumably partly with reference to this triumph that the tribunes spoke of the people waiting to see the great Pompey." (Asinov's Guide to Shakespeare, Vol. One, pp. 255-256)
Since Pompey was not from an Aristocratic background, he wasn't trusted by the senators because they had learned from past experience that successful generals of the non-aristocratic classes could be dangerous.
Pompey tried to prove his loyalty to the senators by disbanding his army after his victoris in 61 B.C. All Pompey achieved WA a loss of influence. He couldn't even persuade the Senate to approve the award of bonuses and land that he had promised to his loyal soldiers.
The First Triumvirate is Formed
Pompey joined in a triumvirate (alliance of three men) with a wealthy business man named Marcus Licinius Crassus and with Julius Caesar. In 60 B.C., the three men formed the First Triumvirate and ruled Rome. They divided the Roman Empire among themselves, but their rule didn't last very long.