Thanks to a legal dispute started early between the municipalities Mörel, Mörel Bitsch on the one hand and the municipalities Naters and Rischinen on the other hand, we are aware of the extension of the Great Aletsch glacier around the mid-18th century. There was disagreement between the mentioned municipalities about the ownership on the western slope of the Riederhorn. Bone of contention was the exact border line between the municipality territories. A first trial in 1684 could settle the dispute only temporarily. The municipalities have been forced seventy years later to execute a new process, which lasted from 1754 to 1755. Again the court did not came to a judgment to everyone's satisfaction. In fact, in the years 1855 to 1856 the high court was engaged a third time to find a clarifying decision in the same matter. The process documents from 1754/55 included a plan elaborated by the authorities from Naters as illustrative drawings. The plan shown here is a faithful copy of the plan and was elaborated in 1855/56 for municipalities Ried-Mörel, Mörel and Bitsch, when the process started again. On the far left the illustrator has included the tongue end of the Great Aletsch glacier ("Alez Glacier"). Since the topographical conditions are shown remarkably well, the mid-18th century extension of the glacier tongue can be estimated quite accurately. The Great Aletsch glacier was then 900 to 1000 meters shorter than during the peak in 1859/60. The landmarks of the borders between the municipalities in 1755/56 carved into the rock, were included as well. Along the trail from Riederfurka to Blatten there are two of these landmarks.