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.
While already the Latin version of the title of this work is given in two versions (De re publica and De Republica), depending on source, the translation of the title of this work show even more variants, often based on the choice of the translator: the expression "res publica" (which appears in the title of this work) is notoriously difficult to translate. Its modern English cognate, republic, (also similar terms in many other languages) has acquired quite different connotations from the original Latin meaning (res publica = most literally "the public matter"), rendering the term here problematic if not outright anachronistic in its implications. Because of the difficulties the title affords, there is no general consensus on how best to retain the sense of the Latin in translating the title. It is helpful to note that Cicero almost certainly had in mind the title of Plato's celebrated dialogue Republic (Greek: Πολιτεία, Politeia) when naming his dialogue. While Plato's dialogue is often translated as Republic, politeia translates more literally as "constitution," "regime," or "set-up," and the long tradition of calling the dialogue The Republic can be attributed to Cicero's own treatise and treatment in Latin.