This is from 1838 and yet another bizarre and archaic usage of the term - Tatar.
This author includes Russians, Poles and Croats as members of the Tatar family due to our ancestral linkage through Noah.
The Shajrat Ul Atrak, Or Genealogical Tree of the Turks and Tatars; Tr. [From the Pers.] and Abridged by Col. Miles
It's extensive and here.