The Marca Geronis (march of Gero) was a vast super-march in the middle of the tenth century. It was created probably for Thietmar (in the 920s) and passed to his two sons consecutively: Siegfried and Gero. On Gero's death in 965 it was divided into five (sometimes six) different marches: the Nordmark, the Ostmark, Meissen, Zeitz, and Merseburg.