Even in the 10th century the Lithuanian stem was divided into three main branches:--the _Borussians_ or _Prussians_; the _Letts_ (who call themselves _Latvis_, whilst the name under which they are known in Russian chronicles, _Letygola_, is an abbreviation of _Latvin-galas_, "the confines of Lithuania"); and the _Lithuanians_, or rather _Lituanians_, _Litva_ or _Letuvininkaï_,--these last being subdivided into Lithuanians proper, and _Zhmud'_ (_Zmudz_, _Samogitians_ or _Zemailey_), the "Lowlanders." To these main branches must be added the _Yatvyags_, or _Yadzvings_, a warlike, black-haired people who inhabited the forests at the upper tributaries of the Niemen and Bug, and the survivors of whom are easily distinguishable as a mixture with White-Russians and Mazurs in some parts of Grodno, Plotsk, Lomza and Warsaw. Nestor's chronicle distinguishes also the _Zhemgala_, who later became known under the name of _Semigallia_, and in the 10th century inhabited the left bank of the Duna. Several authors consider also as Lithuanians the _Kors_ of Russian chronicles, or _Courons_ of Western authors, who inhabited the peninsula of Courland, and the _Golad_, a clan settled on the banks of the Porotva, tributary of the Moskva river, which seems to have been thrown far from the main stem during its migration to the north. The _Krivichi_, who inhabited what is now the government of Smolensk, seem to belong to the same stem. Their name recalls the Krive-Kriveyto, and their ethnological features recall the Lithuanians; but they are now as much Slavonic as Lithuanian.