The Germany and the Agricola of Tacitus by Caius Cornelius Tacitus

According to Wikipedia: Publius (or Gaius) Cornelius Tacitus (AD 56 – AD 117) was a senator and a historian of the Roman Empire. The surviving portions of his two major works—the Annals and the Histories—examine the reigns of the Roman Emperors Tiberius, Claudius, Nero and those who reigned in the Year of the Four Emperors. These two works span the history of the Roman Empire from the death of Augustus in AD 14 to (presumably) the death of emperor Domitian in AD 96. There are enormous lacunae in the surviving texts, including one four books long in the Annals. Other works by Tacitus discuss oratory (in dialogue format, see Dialogus de oratoribus), Germania (in De origine et situ Germanorum), and biographical notes about his father-in-law Agricola, primarily during his campaign in Britannia (see De vita et moribus Iulii Agricolae).