Final answer:
The stress of war affects Cassius and Brutus by causing mental strain and discord, as seen through historical accounts of Roman conflicts and reflected in Shakespeare's portrayal.
Step-by-step explanation:
We can infer that the stress of war has gotten to Cassius and Brutus when they exhibit signs of mental strain, disagreement, and instability in their decisions and actions. Throughout history, numerous accounts suggest that prolonged conflicts greatly impact the wellbeing of those involved, leading to high stress and altered behaviors. Examples such as Roman senators fearing for their power, civil unrest, and leaders engaging in battle themselves, all reflect the pressures that war exerts on individuals. In Shakespeare's play Julius Caesar, both Cassius and Brutus face internal conflicts and external pressures that hinder their judgement and relationships.