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.

In 2009 the oldest documents concerning the place Greiz in Eastern Thuringia were published by a historian. This article now provides a linguistic approach to that publication and its interpretation of the mentioned area in Medieval times. The results may be considered as a contribution to a book of reference for place names of Eastern Thuringia. In this respect some questions have been asked, e. g. whether the region along the river Weiße Elster between the places Weida and Plauen had really been an unsettled area until the 12th century. There is hard evidence that the historian’s assumptions are wrong because of the obvious Slavonic names of settlements in this area dating from the 8th until the 10th centuries. Based on a document from 1209 – respectively its copy from 1510 – as well as on a document from 1225 several facts are discussed in detail with consequences for toponymy and history of settlement with the help of historical linguistics. Thus it becomes evident that it is necessary to exchange ideas and to communicate for representatives of history as well as linguistics. At the same time it is obvious that the publication of documents and their analysis by historians will always be very helpful for linguistic exploitation. As a result the prospective edition of a historical dictionary of place names in Thuringia or of Eastern Thuringia respectively has been asserted as dependent on the continuous co-operation between historians and linguists.