"The Seventh Letter" is a letter written by the philosopher Plato, addressed to Dion, a close friend and former student. It is a personal and philosophical reflection on Plato's life, his teachings, and his relationship with Dion. In the letter, Plato describes how he came to philosophy, and how he was inspired by Socrates, his mentor and friend. He also discusses his travels, including his time in Syracuse, where he was invited by Dion's brother-in-law, Dionysius the Younger, to serve as his adviser.