Cicero has traditionally been considered the master of Latin prose. The writing he produced from about 80 BC until his death in 43 BC exceeds that of any Latin author whose work survives in terms of quantity and variety of genre and subject matter, as well as possessing unsurpassed stylistic excellence. Cicero's many works can be divided into four groups: (1) letters, (2) rhetorical treatises, (3) philosophical works, and (4) orations. His letters provide detailed information about an important period in Roman history and offer a vivid picture of the public and private life among the Roman governing class. Cicero's works on oratory are our most valuable Latin sources for ancient theories on education and rhetoric. His philosophical works were the basis of moral philosophy during the Middle Ages. His speeches inspired many European political leaders and the founders of the United States.