Germanic peoples lived in what is now Poland for several centuries, during which many of their tribes also migrated southward and eastward (see Wielbark culture). With the expansion of the Roman Empire, the Germanic tribes came under Roman cultural influence. Some written remarks by Roman authors that are relevant to developments on Polish lands have been preserved; they provide additional insights in conjunction with the archeological record. In the end, as the Roman Empire was nearing its collapse and the nomadic peoples invading from the east destroyed, damaged or destabilized the various Germanic cultures and societies, the Germanic peoples left Eastern and Central Europe for the safer and wealthier southern and western parts of the European continent. According to Tacitus and Ptolemy, the Goths left the lower Vistula region in the mid-2nd century AD.