There are several historians and authors from whom we owe a debt to, because these writers have handed down some of the knowledge that we have of Ancient Rome.
Titus Livius, also known by modern readers as Livy, was the author of Ab urbe condita (From the City’s Founding). Ab urbe condita begins with Aeneas arriving in Rome and ends with the decline of the Roman monarchy. Livy believed that there was a strong correlation with good morals and the success of a nation. He often argued that the reason why Rome was able to conquer other nations was because Roman leaders had good morals. For instance, Livy argued that the reason the Macedonians were defeated by the Romans was because the Macedonians mimicked the Greeks in loving wine and luxury.
While Livy was eloquent and verbose, Tacitus was simple and concise. His longest and most well known work was called Ab excessu divi Augusti (From the death of the divine Augustus), and chronicled the reigns of Tiberius, Caligula, Claudius and Nero. Many of his commentary on the emperors are pejorative, mainly because he believed the emperors to have loose morals. Tacitus also wrote De Origine et situ Germanorum (Concerning the Origin and Situation of the Germanics). He called the Germanic tribes as barbaric, but praised them for their bravery, which was a quality admired by the Ancient Romans.
Gaius Suetonius Tranquillus, also known as Suetonius, is best known for his work De vita Caesarum (On the Life of the Caesars). His work begins with the life of Julius Caesar and ends with the life of Domitian. The veracity of Suetonius’s work has been contested, because he relied on gossip and hearsay, rather than the eyewitness accounts of historians living at the time of the emperors’ reigns. Other criticism of his work draws on the fact that he was more interested in chronicling the life of the emperors, rather than the events that occurred in the emperors’ reigns.
C. Sallustius Crispus, also known as Sallust, was responsible for works like Bellum Catilinae (Catiline War), Bellum Jugurthinum (Jugurthine War), and Historiae (Histories). Sallust was someone who was believed that the Roman Empire was declining, and that this decline was caused by a decline in morals. In Bellum Catilinae, he described Catiline as someone who was ambitious for power and used him as a warning against what could happen in Rome if the same thing occurred again. Sallust works are important because much of what we know about Ancient Roman morals can be attributed to Sallust’s writings.