Treaty of Meerssen

The Treaty of Mersen or Meerssen, concluded on 8 August 870, was a treaty to partition the realm of Lothair II, known as Lotharingia, by his uncles Louis the German of East Francia and Charles the Bald of West Francia, the two surviving sons of Emperor Louis I the Pious. The treaty followed an earlier treaty of Prüm which had split Middle Francia between Lothair I's sons after his death in 855. The treaty is referred to in some Western European historiographies as the third major partition of Francia, all of which took place from August 843 to August 870, through the treaties of Verdun, Prüm and Mersen's. It was followed by the Treaty of Ribemont. TOC In 869, Lothair II died without legitimate children, so his heir was his brother, Emperor Louis II of Italy. As Louis was at that time campaigning against the Emirate of Bari, his uncles, Louis the German and Charles the Bald, took his inheritance. Charles had himself crowned in Metz the same year, but was forced by his brother to partition the short-lived Lotharingia, together with the lands Lothair II acquired after the death of Charles of Provence, as they had agreed at Metz in 868. Their contract of 870 at Meerssen replaced the 843 Treaty of Verdun, after which the Carolingian Empire was also split into three parts, by dividing the northern half of Middle Francia stretching from the Rhone valley to the North Sea, in effect recombining sundered territories of Francia into two larger east and west divisions. However, at this time large parts of the Frisian coast were under Viking control and therefore only divided on paper. The borderline ran roughly along the rivers Meuse, Ourthe, Moselle, Saone and Rhone. In the north, Louis received most of Lothair's Austrasia, with his eastern part including both Aachen and Metz, and most of Frisia. But in the south, while Louis received most of Upper Burgundy that was left to Lothair (after ceding the southern half to Italy), Charles received Lothair's inheritance in Lower Burgundy (including Lyon and Vienne) and a small western part of Upper Burgundy (parts of Portois and Varais (including Besançon)) – this opened him the way to Italy.