Explain how Julius Caesar is vain.

There are several examples of how Julius Caesar is vain throughout the play. Julius Caesar not only dismisses his wife's advice about going to the Senate but also rejects the soothsayers' warnings. He is also reluctant to push away the crown when Mark Antony attempts to place it on his head and makes several vain comments when he addresses the other Senators. During Caesar's conversation with Calpurnia in act 2, scene 2, he displays his narcissistic personality by dismissing her warnings, referring to himself in the third person, and telling her,

Caesar shall forth. The things that threatened me Ne'er looked but on my back. When they shall see The face of Caesar, they are vanishèd (Shakespeare, 2.2.10-12).

Caesar goes on to personify danger and compares himself to a lion by saying,

That Caesar is more dangerous than he. We are two lions littered in one day, And I the elder and more terrible. And Caesar shall go forth (Shakespeare, 2.2.45-48).

Later on, Caesar visits the Senate and refuses to yield to the requests of the senators. Caesar displays his vanity by comparing himself to the North Star and says,

If I could pray to move, prayers would move me. But I am constant as the northern star, Of whose true-fixed and resting quality There is no fellow in the firmament (Shakespeare, 3.1.64-67).

Overall, Caesar's vanity is expressed and depicted by his narcissistic comments and exalted perception of himself.