"Gero I (c. 900 – 20 May 965), called the Great (Latin magnus), ruled an initially modest march centred on Merseburg in the south of the present German state of Saxony-Anhalt, which he expanded into a vast territory named after him: the marca Geronis. During the mid-10th century, he was the leader of the Saxon Ostsiedlung." - (en.wikipedia.org 30.01.2020)
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