Antes and Sclavenes around 500 AD according to Jordanes
The earliest detailed description of Slavic territory as it was around year 500 AD comes from Procopius and Jordanes, but it is quite possible that they did not have full knowledge about the extent of Slavic lands – especially in the north, north-west and north-east.
However, their precise description of the extent of Slavs in the immediate borderland/neighbourhood of the Byzantine Empire is probably reliable. Procopius wrote that they lived north of the Danube, and Jordanes provided even more details, as he wrote:
“Within these rivers lies Dacia, encircled by the lofty Alps as by a crown. Near their left ridge, which inclines toward the north, and beginning at the source of the Vistula, the populous race of the Venethi dwell, occupying a great expanse of land. Though their names are now dispersed amid various clans and places, yet they are chiefly called Sclaveni and Antes.
The abode of the Sclaveni extends from the city of Noviodunum and the lake called Mursianus to the Danaster, and northward as far as the Vistula. (…) The Antes, (…) dwelling above the curve of the sea of Pontus, spread from the Danaster to the Danaper, rivers that are many days’ journey apart.”
Lake Mursianus was in fact, according to the majority of researchers, the vast marshes at the juncture of the Drava and the Danube; the lake or marshes in question might have extended as far as to the juncture of the Tisza and the Danube. The lake’s name was derived from the town of Mursa (present-day Osijek). The Alps are what we today call the Carpathians. The source of the Vistula is located close to the present-day Bielsko-Biała. Danaster refers to Dniester, Danaper refers to present-day Dnieper. And “the curve of the sea of Pontus [Black Sea]” was the coastline (which forms a nice curve) in the region of present-day Odessa.
Therefore, this is how the map would look: