 Complete the following phrase:  Polybius wrote several works, the majority of which are lost. His earliest work was a biography of the Greek statesman Philopoemen; this work was later used as a source by Plutarch when composing his Parallel Lives, however the original Polybian text is lost. In addition, Polybius wrote an extensive treatise entitled Tactics, which may have detailed Roman and Greek military tactics. Small parts of this work may survive in his major Histories, but the work itself is lost, as well. Another missing work was a historical monograph on the events of the 