North Africa in the wars against Carthage. He was with Scipio at the destruction of Carthage in 146. Diodorus Siculus was a Greek historian who lived in the 1st century BC, around the time of Julius Caesar and Augustus. He wrote a universal history, Bibliotheca Historica, in 40 books. Of these, the first five and the 11th through the 20th remain. The first two parts covered history through the early Hellenistic era. The third part takes the story to the beginning of Caesar's wars in Gaul, now France. Dionysius of Halicarnassus lived late in the first century BC. His history of Rome from its origins to the First Punic War (264 to 241 BC) is written from a Roman point of view, but it is carefully researched. He also wrote a number of other treatises, including On Imitation, Commentaries on the Ancient Orators, and On the Arrangement of Words. The historians Appian of Alexandria and Arrian of Nicomedia both lived in the second century AD. Appian wrote on Rome and its conquests, while Arrian is remembered for his work on the campaigns of Alexander the Great. Arrian served in the Roman army. His book therefore concentrates heavily on the military aspects of Alexander's life. Arrian also wrote a philosophical treatise, the Diatribai, based on the teachings of his mentor Epictetus. Best known of the late Greek historians to modern readers is Plutarch of Chaeronea, who died about AD 119. His Parallel Lives of great Greek and Roman leaders has been read by every generation since the work was first published. His other surviving work is the Moralia, a collection of essays on ethical, religious, political, physical, and literary topics. During later times, so-called "commonplace books," usually describing historical anecdotes, became quite popular. Surviving examples of this popular genre include works such as Aulus Gellius's Attic Nights, Athenaeus of Naucratis's Deipnosophistae, and Claudius Aelianus's De Natura Animalium and Varia Historia. Science and mathematics The physician Galen lived during the 2nd century AD. He was a careful student of anatomy, and his works exerted a powerful influence on medicine for the next 1,400 years. Strabo, who died about AD 23, was a geographer and historian. His Historical Sketches in 47 volumes has nearly all been lost. His Geographical Sketches remain as the only existing ancient book covering the whole range of people and countries known to the Greeks and Romans through the