Memorabilia (or The Memorable Thoughts of Socrates) is a collection of Socratic dialogues by Xenophon, a student of Socrates. The lengthiest and most famous of Xenophon's Socratic writings, the Memorabilia is essentially a defense of Socrates, offering edifying examples of Socrates' conversations and activities along with occasional commentary from Xenophon. It was completed after 371 BC. Socrates (circa 469 BC - 399 BC) was a classical Greek Athenian philosopher. Credited as one of the founders of Western philosophy, he is an enigmatic figure known chiefly through the accounts of later classical writers, especially the writings of his students Plato and Xenophon, and the plays of his contemporary Aristophanes. Xenophon (circa 430 - 354 BC), son of Gryllus, also known as Xenophon of Athens, was a Greek historian, soldier, mercenary, philosopher and a contemporary and admirer of Socrates. He is known for his writings on the history of his own times, the 4th century BC, preserving the sayings of Socrates, and descriptions of life in ancient Greece and the Persian Empire.