by claiming the title Dei gratia id quod sum: by the Grace of God, that is what I am. He also claimed that his imperial father-in-law had named him as his heir. On 15 October 879, the bishops and nobles of the region around the Rhône and Saône rivers assembled in the Synod of Mantaille. They elected Boso king and successor to Louis the Stammerer, the first non-Carolingian king in Western Europe in more than a century. This event was the first "free election" among the Franks, without regard to royal descent, inspired by a canonical principle (but not constant practice) of ecclesiastical elections. Boso's realm, usually called the Kingdom of Provence, comprised the ecclesiastical provinces of the archbishops of Arles, Aix, Vienne, Lyon (without Langres), and probably Besançon, and the dioceses of Tarentaise, Uzès, and Viviers. After Louis and Carloman divided their father's realm at Amiens in March 880, the two brothers joined to march against Boso. They took Mâcon and the northern parts of Boso's realm. Then uniting their forces with those of Charles the Fat, they unsuccessfully besieged Vienne from August to November. In August 882, Boso was again besieged at Vienne by his brother, Richard the Justiciar, duke of Burgundy and count of Autun, who took the city in September. Boso never regained much of his realm and was restricted to the county of Vienne. He died in 887 and was succeeded by his son Louis the Blind. Marriages Boso was married twice. The identity of his first wife is not known; his second wife was Ermengard of Italy, whom he wed in March 876. Their issue was: Guilla of Provence (December 873 – before 15 June 929), married firstly Rudolph I of Burgundy, secondly Hugh of Italy; her mother is reported to have been Ermengard, but this seems to be erroneous because she was born before Boso and Ermengarde's wedding Engelberge/Ethelberga, married William I, Duke of Aquitaine; her mother is reported to have been Ermengard Louis the Blind (before 884 – 5 June 928), possibly had a non-marital relationship, next supposedly married Anna/Eudocia Mamikonian (according to a letter that Christian Settipani attributes to Nicholas Mystikos), lastly married Adelaide of Burgundy, who might have been a daughter of his sister Guilla; his mother is reported to have been Ermengard Notes References Sources Further reading MacLean, Simon. "The Carolingian Response to the Revolt of Boso, 879–887." Early