Imperial Rome refers to the period of Roman history from 27 BCE, when Augustus became the first emperor, until the fall of the Western Roman Empire in 476 CE. This era is marked by significant territorial expansion, cultural achievements, and the establishment of a complex government system. The empire reached its greatest extent under Trajan, encompassing vast regions across Europe, North Africa, and parts of Asia. During this time, Roman architecture flourished, leading to the construction of iconic structures like the Colosseum and Pantheon. The empire also saw advancements in law, engineering, and the arts, influencing future civilizations. The Pax Romana, a long period of relative peace, allowed trade and culture to thrive across the empire.