Throughout his later life, Plato became entangled with the politics of the city of Syracuse. According to Diogenes Laërtius, Plato initially visited Syracuse while it was under the rule of Dionysius. During this first trip Dionysius's brother-in-law, Dion of Syracuse, became one of Plato's disciples, but the tyrant himself turned against Plato. Plato almost faced death, but he was sold into slavery. Anniceris, a Cyrenaic philosopher, subsequently bought Plato's freedom for twenty minas, and sent him home. After Dionysius's death, according to Plato's "Seventh Letter", Dion requested Plato return to Syracuse to tutor Dionysius II and guide him to become a philosopher king. Dionysius II seemed to accept Plato's teachings, but he became suspicious of Dion, his uncle. Dionysius expelled Dion and kept Plato against his will. Eventually Plato left Syracuse. Dion would return to overthrow Dionysius and ruled Syracuse for a short time before being usurped by Calippus, a fellow disciple of Plato.