Answer:
There are many known Roman historians. Some of them are: Dionysius of Halicarnassus, Plutarch, Livy, Polybus, Appian, Paterculus, Sallust, Caesar, Dio Cassius, Tacitus, and Suetonius. In addition to the historians many prominent Romans also wrote their autobiographies or memoirs which are also considered a type of history.
The "big three" are Tacitus, Seutonius and Dio, but there were many others, such as Appian, Livy and Polybius.