Final answer:
The Roman Empire reached its largest extent under Emperor Trajan in 117 CE, spanning across parts of Europe, North Africa, and the Middle East and marked by grand infrastructure like Hadrian's Wall.
Step-by-step explanation:
The Roman Empire at Its Largest Extent
When studying the history of the Roman Empire, one notable period to examine is when the Empire reached its maximum size, a feat achieved by Emperor Trajan in 117 CE. During Trajan’s rule, the Empire expanded across three continents, encompassing most of modern-day England, Germany, Romania, North Africa including present-day Morocco, and extending to the borders of the Parthian Empire to the east. The Empire was characterized by formidable military strength, sophisticated engineering, and architecture, as reflected in the infrastructure such as roads, fortifications, and public baths it created.
Boundaries were reinforced by the construction of the limes, extensive fortifications such as Hadrian’s Wall in northern England, which were designed to ward off invasions and consolidate imperial control. To the north and northeast, Rome encountered vast inhospitable lands and the so-called 'barbarians' while to the east, the Persians under the Parthian and later Sassanid empires were recognized as Rome’s only civilized counterparts. This maximum territorial expanse under Trajan significantly shaped the cultural and political landscapes within these regions.