This thesis traces the metaphorical language of slavery across the Platonic corpus, arguing that Plato’s political theory emerges in response to Socrates choosing to die a ‘good slave’ to both the laws and the gods. Socrates makes this choice, I argue in Chapter 1, because of his understanding of justice and piety as outlined in the Euthyphro: justice is voluntary slavery to the laws, and piety is voluntary slavery to the gods. But Plato, unhappy with the death of his mentor, revises this account of justice. According to the Gorgias and the Republic, as I claim in Chapter 2, justice demands that the philosopher be a master, not a slave; piety, meanwhile, takes a backseat. In the Statesman (Chapter 3), piety returns: before a philosopher can rule in accordance with justice, he must first serve the gods as ‘priest’ and ‘prophet’ of dialectic. But since the rule of the priest-king is not practical in the long run, Plato in the Laws revives the Euthyphro’s account of justice and piety and finds a new way to rescue philosophers from Socrates’ fate (Chapter 4): he envisions a city in which all citizens are good slaves to the laws and the gods. And these good slaves will, like Socrates, in death earn manumission and entry into what I describe in the Epilogue as the divine, paradigmatic polis.