In the modern era, the archaeologist Hugo Winckler (1863–1913) was the first to associate the Sakas with the Scythians. John Manuel Cook, in "The Cambridge History of Iran", states: "The Persians gave the single name Sakā both to the nomads whom they encountered between the Hungry Steppe (Mirzacho'l) and the Caspian, and equally to those north of the Danube and Black Sea against whom Darius later campaigned; and the Greeks and Assyrians called all those who were known to them by the name Skuthai (Iškuzai). Sakā and Skuthai evidently constituted a generic name for the nomads on the northern frontiers." Persian sources often treat them as a single tribe called the Saka ("Sakai" or "Sakas"), but Greek and Latin texts suggest that the Scythians were composed of many sub-groups.