There's no better way of learning about history than from those who were there, and many of the key classical sources can be read in freely available, albeit older, scholarly editions online. There is a lot to be said for starting at the beginning and following the story through the generations. Not least because the two earliest classical historians are also two of the greatest.
Herodotus wrote a generation after the Persian Wars which he recounted in The Histories, but his reputation as the 'father of history' perhaps stands higher today than it did in later antiquity. The central confrontation between Greek and Barbarian provides the framework for a series of digressions that add up to an anthropological portrait of the whole Mediterranean world.
Thucydides inaugurated a less expansive genre of history with a sharp focus on politics and military affairs. His History of the Peloponnesian War, with its combination of rigour, realism, but also subtle rhetoric, has proved politically influential down to our own day.
Xenophon began his history of Greece, the Hellenica, where Thucydides broke off, though the continuation is generally considered inferior. He was also the author of the Anabasis, an eye-witness account of a mercenary expedition into the Persian Empire. The story of his adventure is said to have been read with care by Alexander the Great, and this simple soldier was often seen as an appropriate figure to introduce young scholars to the Greek language.
Polybius, a Greek statesman and client of the Roman Scipio was the first Greek historian to recount the emergence of Rome as a Mediterranean power, in his Histories.
Sallust's two best known works bring the reader into the heart of the political struggles in late Republican Rome. The Jugurthine War serves as the backdrop to the partisan struggle between Marius and Sulla. The Cataline Conspiracy illuminates the role of figures such as Cicero and Caesar as the Republic reached the point of breakdown.
Julius Caesar himself was an accomplished historian in commentaries whose Thucydidean rigour provided an effective rhetorical vehicle for his own partisan standpoint. His account of The Gallic War is important as an early firsthand account of Northwest Europe. In the original, it has often played the role for students of Latin, that Xenophon plays for students of Greek. The Civil War recounts the outbreak of conflict with his rival Pompey, and his appointment as Dictator of Rome. The Alexandrian War, The Spanish War, and The African War, are generally thought to be the work of Caesar's officers.
Tacitus (c.56-117 AD) is perhaps the greatest of Roman historians. In his account of the early empire we see at once the 'red Tacitus' who looks back to republican values, and the 'black Tacitus' who sees the forces that made the new order inevitable. The Annals documents the early imperial period from the death of Augustus to the reign of Nero. The Histories describes the intense struggles of the Year of the Four Emperors and gives a Roman perspective on the Jewish people on the eve of the Great Revolt. In his Agricola, Tacitus showed how patriotic service was still possible in outlying provinces like Britain. In the Germania, a pioneering ethnographic account of Northern Europe, he helped to inaugurate the myth of the noble savage, through his contrast between German virtues and Roman vices.
Josephus recorded the history of the Great Revolt in his On the Jewish War, a work which he was uniquely placed to write. Initially the commander of Jewish forces in Galilee, Josephus surrendered under circumstances which historians have often found discreditable, and became a client of the Flavian dynasty founded by the Roman commander Vespasian.
Suetonius served as director of the imperial archives under Trajan. His Lives of the Twelve Caesars is notorious for the gossipy anecdotes recorded as part of his attempt to convey the character of Rome's rulers.
Ammianus Marcellinus, a soldier born in the Greek-speaking east was the last of the great classical historians to write in Latin. His Res Gestae is a key source on a Fourth Century Empire facing mounting external threats as well as internal social change, addressing the rise of Christianity from a tolerant pagan point of view.
Not all the great classical historians fit into this chronological scheme. Many surviving authors were compilers or commentators on earlier writers. Those in this category include:
Livy: In his account of Rome From the Foundation of the City, the great historian of Augustan Rome made use of many earlier writers now lost. His account of early Rome begins in legend, and occassionally appears to adapt Greek history wholesale, but he remains important for his account of Rome's rise to dominance in Italy, and its epic struggle with Carthage.
Plutarch: By taking a comparative approach in his Parallel Lives of leading Greek and Roman statesman, Plutarch made a unique contribution to the genre of biography that has made him one of the most widely read classical authors over the centuries.