Do the fourth to the sixth centuries deserve to be thought of as the period of the migration of peoples, or even of the barbarian migrations? Human beings have migrated across the planet's surface since mankind's first appearance and it cannot seriously be argued that population movement alone differentiates the period that concerns us. It is difficult, too, to argue that this era is distinguishable from others even in terms of the scale of such movement. It is a truism that the modern period has seen the migration of infinitely larger groups of people than migrated in the fourth and fifth centuries but the point holds even when looking only at Roman history. It is impossible to obtain an accurate figure for the numbers of people who moved between the Gothic crossing of the Danube in 376 and the Lombard invasion of Italy in 568 but even on the most maximalist interpretation they cannot have formed more than a small percentage of Europe's population. Barbarians had been entering Roman territory since the Republic. The last people before Alaric to capture Rome had been invading Gauls. An attack upon Italy by the northern German Cimbri and Teutones had required hard fighting. Caesar met the migration of the Helvetii, and so on. Once the Empire had established its frontiers along the Rhine and Danube, groups from barbaricum continued to petition for entry into Roman territory, which they were frequently granted. It is difficult to estimate the size of the groups involved.