De re publica (On the Commonwealth; see below) is a dialogue on Roman politics by Cicero, written in six books between 54 and 51 BC. The work does not survive in a complete state, and large parts are missing. The surviving sections derive from excerpts preserved in later works and from an incomplete palimpsest uncovered in 1819. Cicero uses the work to explain Roman constitutional theory. Written in imitation of Plato's Republic, it takes the form of a Socratic dialogue in which Scipio Aemilianus takes the role of a wise old man. The work examines the type of government that had been established in Rome since the kings, and that was challenged by, amongst others, Julius Caesar. The development of the constitution is explained, and Cicero explores the different types of constitutions and the roles played by citizens in government. The work is also known for the Dream of Scipio, a fictional dream vision from the sixth book. Source: Wikipedia (en)