Hellenistic historiography. After the groundbreaking work of the Greek historians Herodotus, Thucydides, Xenohpon, and to some extent Aristotle, interest in developing and refining methods of historical research waned. Writers became more concerned to write "realistic" and moving (read "melodramatic") histories that, although they attracted a wider audience, lacked accuracy and learning. Interest focussed on the will and passion of individuals, rather than economics, politics, etc. This school of historiography drew heavily on oratorical theory and technique (e.g. that of the Greek orator Isocrates) in its quest to move and excite its audience.
Native Roman historiography. From the beginning of Rome to 400 B.C. only scant records were kept, but by 300 B.C. the tabulae pontificum gave regular records of magistrates and cult importance (e.g. anomalous births, wonders, etc.) These tables were the first annals, from which Ennius took the title of his historical epic, but their character was still purely sacral in Cato's day. Cato the Elder first inspired interest in the prose history of Roman antiquities, with his researches into the origins of Roman law, custom, and history in the Origines. Though his style is harsh, nearly everyone praises the quality of his research, which included the study of pontifical law, cult and constitutional antiquities, and public and private law. Followers in his path were, among others, Cassius Hemina and Calpurnius Piso. The annales maximi, first published c. 123 B.C., a definitive work of annalistic reconstruction in 80 books, virtually definined the genre of annalistic historiography, which influenced nearly every subsequent Roman historian. They set out in formal arrangement year by year the official events of the State, viz. elections and commands, civic, provincial, and cult business. Most Roman historians through the Augustan and Silver ages show a blending of the annalistic and Hellenistic styles of history writing.
Fabius Pictor Roman Senator and historian who took part in the Second Punic War, consulting the Delphic Oracle after the battle of Cannae. Wrote a history of Rome in Greek, the first of the senatorial histories relating Roman history to the Greek world: his audience was presumably those Greeks interested in learning about the new kid on the block (Rome). He traced Rome from Aeneas to his own day. Probably not annalistic in his treatment.
Polybius (203?-120) Greek historian of Rome. He was captured in the Third Macedonian War and sent to Rome, where he was befriended by Aemelius Paullus and Scipio Aemelianus. His Universal History (written in Greek) covered the period from the First Punic War to the final conquest of Spain, Africa, and Greece (144).
Valerius Antias A Sullan annalist, wrote a history of Rome in at least 75 books, from the origins to his own times. He represents the Hellenistic, particularly Isocratean, fashion in historiography, elaborating battle scenes, inventing casualty figures, and rhetorically composing speeches and debates. "To information often false he added confusion and misrepresentation, under the political and family influences of his time" (OCD). Livy criticizes his numbers but followed him thoughout his work. His style was "vigorous and rhetorical, if without grace," apparently the best literary historian before Livy.
Claudius Quadrigarius A Sullan annalist, wrote a history of Rome in at least 23 books, fromt the Gallic sack to his own times. He may also have been a Hellenistic, Isocratean stylist. His style was simple, his vocabulary plain. Livy followed him closely.
Licinius Macer Roman annalist. Tribune in 73, praetor in 68-67, was convicted of extortion and committed suicide in 66. Wrote a history of Rome in 16 books, beginning with Rome's origins: endpoint is unknown.
Aelius Tubero Contemporary of Pompey and Caesar, who sided first with Pompey., but later was reconciled to Caesar. He treated Roman history from the beginning to his own time in at least 14 books.
Dionysius of Halicarnassus Rhetor and historian, taught at Rome 30-8 B.C. Wrote Roman Antiquities covering the founding to the First Punic War in 20 books; highly rhetorical, but not considered reliable.