Complex sentence: The Caspians have generally been regarded as a pre-Indo-European people; they have been identified by Ernst Herzfeld with the Kassites, Herzfeld, "The Persian Empire", (Wiesbaden) 1968:195-99, noted by Rüdiger.
Split into simpler sentences: The Caspians have generally been regarded as a pre-Indo-European people. They have been identified by Ernst Herzfeld with the Kassites, Herzfeld, "The Persian Empire", (Wiesbaden) 1968:195-99, noted by Rüdiger.