Marca Geronis

The Marca Geronis or March of Gero[1] was a vast super-march in the middle of the tenth century.

On Gero's death in 965 it was divided into five different marches: the Nordmark, Ostmark, Meissen, Zeitz, and Merseburg.

Because the Marca Geronis was created simultaneously with the March of Billung to the north, it is sometimes said to be the southern half of the Ostmark.

"[2] Within the span of one page, James Westfall Thompson refers to it as both the "Sorben Mark" and the "Thuringian March".

[3] Part of the complication involved in ascertaining the territoriality of the march over which Gero ruled is the nature of the margravial title in tenth-century Saxony.

The hatched portion of the map in the northeast excepting the March of the Billungs was the Marca Geronis , notice the Mark Merseburg which was one of its partitions.