Analysis of information sources in references of the Wikipedia article "Иранские народы" in Russian language version.
The Azerbaijani are of mixed ethnic origin, the oldest element deriving from the indigenous population of eastern Transcaucasia and possibly from the Medians of northern Persia. This population was Persianized during the period of the Sāsānian dynasty of Iran (3rd-7th century ce).
.."The Ossetians, calling themselves Iristi and their homeland Iryston are the most northerly Iranian people. … They are descended from a division of Sarmatians, the Alans who were pushed out of the Terek River lowlands and in the Caucasus foothills by invading Huns in the 4th century AD."
The Azerbaijani are of mixed ethnic origin, the oldest element deriving from the indigenous population of eastern Transcaucasia and possibly from the Medians of northern Persia. This population was Persianized during the period of the Sāsānian dynasty of Iran (3rd-7th century ce).