Today, this area corresponds mostly to the Podlaskie Voivodeship in Poland, portions of Lithuania west of the Nemunas and a part of Hrodna Province in Belarus.
The territory was between the later cities of Marijampolė and Merkinė (Lithuania), Slonim and Kobryn (Belarus), and Białystok and Lyck in Prussia (now Ełk, Poland).
[citation needed] In the Hypatian Codex the spelling changes: Jatviagy, Jatviezie, Jatviažin, zemlia Jatveskaja, na zemliu Jatviažs´kuju and more.
[citation needed] This name was taken by the papal administration: terra Jatwesouie, Gretuesia, Gzestuesie, Getuesia und Getvesia.
[citation needed] In two dotations, in 1253 and 1259, by Mindaugas, a new name was recorded: Dainava, Deynowe, Dainowe, Denowe (land of songs).
In the sentence of Breslau of the emperor Sigismund of Luxembourg to the Livonian Order from 1325, this area is called Suderlandt alias Jetuen.
[citation needed] Vytautas the Great wrote about "terra Sudorum", in a letter to King Sigismund of March 11, 1420.