the Don river and invaded Scythia starting in the late 4th century and the early 3rd century BCE. The Massagetae themselves merged with tribal groups in Central Asia to form the Alans, a people who themselves belonged to the larger Sarmatian group. Related to the Asii who had invaded Bactria in the 2nd century BCE, the Alans were pushed by the Kang-chü people to the west into the Caucasian and Pontic steppes, where they came in contact and conflict with the Parthian and Roman empires. By the 2nd century CE, they had conquered the steppes of the north Caucasus and the north Black Sea area and created a powerful confederation of tribes under their rule. In 375 CE, the Huns conquered most of the Alans living to the east of the Don river, massacred a significant number of them and absorbed them into their tribal polity, while the Alans to the west of the Don remained free from Hunnish domination and participated in the movements of the Migration Period. Some free Alans fled into the mountains of the Caucasus, where they participated in the ethnogenesis of populations including the Ossetians and the Kabardians, and other Alan groupings survived in Crimea. Other free Alans migrated into Central and then Western Europe, from where some of them went to Britannia and Hispania, and some Alans joined the Germanic Vandals into crossing the Strait of Gibraltar and creating the Vandal Kingdom in North Africa. Legacy Byzantine authors later used the name "Massagetae" as an archaising term for the Huns, Turks, Tatars and other related peoples who were completely unrelated to the populations the name initially designated in Antiquity. A 9th century work by Rabanus Maurus, De Universo, states: "The Massagetae are in origin from the tribe of the Scythians, and are called Massagetae, as if heavy, that is, strong Getae." In Central Asian languages such as Middle Persian and Avestan, the prefix massa means "great," "heavy," or "strong." Some authors, such as Alexander Cunningham, James P. Mallory, Victor H. Mair, and Edgar Knobloch have proposed relating the Massagetae to the Gutians of 2000 BC Mesopotamia, and/or a people known in ancient China as the "Da Yuezhi" or "Great Yuezhi" (who founded the Kushan Empire in South Asia). Mallory and Mair suggest that Da Yuezhi may at one time have been pronounced d'ad-ngiwat-tieg, connecting them to the Massagetae. These theories are not widely accepted,