500
"CAESAR: ...But I am constant as the Northern Star, of whose true fixed and resting quality there is no fellow in the firmament..." (Pg. 97, Line 66) (read entire passage in book)
Simile--Caesar compares the firmness of his decision to the fixed position of the Northern Star. Just like the star will never move from it's place, Caesar will never change his mind in banishing Publius.
Analogy--Caesar compares the sky to the world. The sky is full of stars, each one shining, but only the Northern star firmly holds its position The world is full of people, each one made of skin and blood, but only one (Caesar) remains firm in his rank.