The expression he has on this face is showing that he's not afraid of anything in his way.
Crossing the Rubicon
Crossing the Rubicon was the equivalent of declaring war on Rome. When Cesear crossed the Rubicon he had an army with him who'd fight with him until they died. The die is cast means that Cesear can't go back and that this is his choice that he can't take back.
The Ides of March
On the Ides of March Cesear was stabbed by the senators killing him. Cesar was fighting against the senators until he saw brutus stab him then he gave up. This impacted rome because they lost there leader and it ended Cesuras dictatorship but still angered many people.
Cesear and the Republic
Cesar effected the republic in many ways. One of these ways was the fact he was part of the first triumvirate. Another way was that he was hated by the senators yet still remained in office but was exiled yet still came back. He was the first dictator for life giving him the most power of anyone person in there life. These are three ways that Julius Cesear affected the republic.