The crossword solution for the term 'Historian Understood Country' is Tacitus (7 letters). Tacitus was a Roman historian who lived in the 1st century AD. He is best known for his works on the history of the Roman Empire, including his most famous work, The Annals. He also wrote Germania, which provided an account of the Germanic tribes and their customs. Tacitus was highly respected for his accurate and detailed accounts of the Roman Empire and its people.