In this article the Nienburg fragment from about 1180 is under linguistic scrutiny. The three eastern provinciae of the Nienburg Monastery situated in the historical eastern Lusatia are differentiated with help of linguistic methods according to particular paragraphs of the document. Special attention is given to some toponyms which could not have been attributed to definite places yet. It is presented a proposal to associate the place names to still existing geographical objects. Furthermore some geographical names are discussed and interpreted in a new way in contrast to former explanations. Thus characteristic feature of the Nienburg fragment becomes obvious: The Latin written document has preserved the Slavonic proper names in a graphic variant very closely to their original forms without reduction or any other influence of the German language on it.