when was the roman empire at its peak
Roman Empire The Empire reached its largest expanse under Trajan (reigned 98–117),[43] encompassing an area of 5 million square kilometres. The traditional population estimate of 55–60 million inhabitants[47] accounted for between one-sixth and one-fourth of the world's total population[48] and made it the largest population of any unified political entity in the West until the mid-19th century.[49] Recent demographic studies have argued for a population peak ranging from 70 million to more than 100 million.[50] Each of the three largest cities in the Empire—Rome, Alexandria, and Antioch— was almost twice the size of any European city at the beginning of the 17th century.[51]