You can not sum like this the populations on the table, because it does not cover the same things all the time. A couple of problems for example: - When a king

You can not sum like this the populations on the table, because it does not cover the same things all the time. A couple of problems for example: - When a kingdom/empire spreads to Africa and Asia, the whole population of the country is counted even though only a part of is in Europe. You can observe that with Muslim caliphates who suddenly appear in the table like Umayyad Caliphate with 29 millions people in 711 when it was not in the table the year before. Between 392 and 484, the Roman Empire lost North Africa and the Middle East, that counts for million of peoples. - Some populations on the map are not represented in the table when they should have a good amount of people, maybe because we don't have estimates of them? I am thinking of the Kingdom of Soissons and the Alemanni in 484. These places are in the ancient Gauls and were fairly populated. On top of that, it was the time known as "Migration Period" where a lot of people moved around (some going out of Europe) and a lot of war happened (hence a lot of death). The population of Western Europe was going down already in the 4th century and it accelerated with the breakdown of the Empire and the rule of law, people started to leave cities and move to the countryside, trade plunged and food was scarce.