Diogenes Laertius or Lartius, a historian of philosophy, is believed to have originated from Laerte in Cilicia and to have lived in the early 3rd century AD, but nothing is known about his life and personality, as he neither provides such information himself nor is there anything related in other ancient writers. His surviving work, in ten books, is titled Lives of Philosophers, and the full title is Lives and Opinions of Eminent Philosophers and Those Pleasing to Each Sect in a Concise Collection. Diogenes gathered his material from the most diverse sources: letters, public documents, philosophical and historical writings, legends, historical anecdotes, as well as comedies and even from the Homeric epics, and mainly from the surviving work of each philosopher. From his sources, he drew a vast amount of knowledge, which he did not critically utilize, and this, according to scholars, shows that apart from his erudition, he did not have substantial philosophical education. The Life of the Cynic Diogenes (who was born in Sinope around 412 BC and died, according to a legend, in 323 in Corinth, on the same day that Alexander the Great passed away in Babylon) is one of the most beautiful texts of this work. Beyond the anecdotes that accompany him, which usually reflect his biting humor that knows no sacred or holy, Diogenes the Cynic was primarily a revolutionary who set out to change the corrupt society of his time, teaching self-sufficiency and frugality, and mocking authority and excess.