Plato tried to create a philosopher-king, and was sold as a slave

Around 388 BC, Plato visited the court of Dionysius I, the powerful tyrant of Syracuse in Sicily. He spoke frankly about justice and tyranny. Dionysius was not amused.

According to ancient biographies, the tyrant had him put on a ship and sold as a slave at the market on the island of Aegina. A philosopher named Anniceris recognised him and paid his ransom. When Plato’s friends tried to repay him, he refused, and the story says the money helped buy the land for the Academy.

Decades later, Plato returned to Syracuse twice, hoping to educate the tyrant’s son, Dionysius II, with the help of his friend Dion. The young ruler grew jealous of Dion, exiled him and kept Plato as a virtual prisoner.

Plato eventually got home and described the failure in his Seventh Letter. He never stopped believing in philosopher-kings, but he learned how hard it is to make one. His last great work, the Laws, is far more practical about what real cities can achieve.