Among the many relevant works, here are some that help provide background for understanding the political aspects of Shakespeare’s plays. They are available in many editions and translations.

Aristotle, Politics

Plato, Republic

Machiavelli, Discourses on Livy

Machiavelli, The Prince

Montesquieu, The Greatness of the Romans and Their Decline

Nietzsche, On the Genealogy of Morals