Cornelius Tacitus was a Roman historian and senator who lived during the 1st century AD. He is known for his works "The Annals" and "The Histories," which provide valuable insights into the history and politics of the Roman Empire. Tacitus is admired for his vivid and dramatic writing style, as well as his critical analysis of the political and social issues of his time. His works continue to be studied and revered for their historical significance and literary merit.