Plebeians of the world, unite! You have nothing to lose but your chains!

Explanation: At the very beginning, the Roman Republic, overthrowing the old Roman Kingdom, preserved primarily the rights of the ‘patricians’ - the old (and often wealthy) established families of Rome. Very quickly after the Republic was established, a series of general strikes would force the patrician class to negotiate with the workers, and eventually afford them near-total legal equality - with the patricians only hanging onto a few token religious offices by the end of the Republic.

Very interestingly, and tellingly, one of the early demands of the plebeians was for laws to be written down and made public, so anyone could read and interpret them. Much harder to nail some fellow too poor to afford legal help on made-up charges if everyone is capable of checking the law!