The Alans were an ancient and medieval Iranic nomadic pastoral people who migrated to what is today the North Caucasus; some continued on to Europe and later North Africa. They are generally regarded as part of the Sarmatians, and possibly related to the Massagetae. Modern historians have connected the Alans with the Central Asian Yancai of Chinese sources and with the Aorsi of Roman sources. Having migrated westwards and becoming dominant among the Sarmatians on the Pontic–Caspian steppe, the Alans are mentioned by Roman sources in the 1st century CE. At that time they had settled in the region north of the Black Sea and frequently raided the Parthian Empire and the South Caucasus provinces of the Roman Empire. Between 215 and 250 CE the Goths broke their hold on the Pontic Steppe, thereby assimilating a significant population of associated Alans.