This study examines the migrations of the Dahae and Sarmatians—the two related early nomadic peoples of Middle Asia and Eastern Europe—directed to the south and west of their homeland. Archaeological, written, and folkloric sources make it possible to trace the migrations of the Dahae and Sarmatians over several centuries preceding the spread of Islam in Central Asia and of Christianity in Old Rus. The study focuses on mortuary monuments, temples, and sanctuaries, cross-shaped in plan view, of migrants and their descendants. A detailed analysis of the major southward migration of Dahae from the Lower Syr-Darya in the late 3rd to early 2nd BC is presented. This migration had a considerable effect on ethnic and cultural processes in Middle Asia. The migration aimed at conquering the lands of Alexander the Great’s descendants, who were rapidly losing control over them. Features of Dahaean culture are noticed in town planning, architecture, mortuary rites, armor, etc. over the entire territory they had captured. Southward migration of the descendants of the Dahae—people of the Kaunchi and Otrar cultures—from the Syr-Darya, led by the Huns, was part of the Great Migration. The Kaunchi people headed toward the oases of Samarkand and Kesh, the Otrar people toward the oasis of Bukhara, and those associated with the Dzhetyasar culture toward the Qarshi oasis. It is demonstrated that while the cross-shaped plan view of religious structures turned into the eight-petaled rosette, the fu neral rite did not change, remains of burials and charcoal are observed everywhere. Relics of the ScythoSarmatian legacy are seen in the culture of Old Rus. For instance, remains of the sanctuaries of Perun are walls and ditches arranged in a cruciform or eight-petaled fashion, fi lled with charcoal and bones of sacrifi ced animals, with a statue of the supreme Slavic deity, in the center. Early sanctuaries of Perun in Kiev and Khodosovichi were cruciate in plan view, while later ones on the banks of the Zbruch and the Volkhov rivers had octopetalous plans. Apparently they were infl uenced by the architectural traditions of Dahae and Sarmatians, who took part in the ethnogenetic processes in both Old Rus and Turan.