Encyclopedia Britannica Online, article titled Boso:
"French BOSON, king of lower Burgundy, or Provence, from 877. The son of Buvin (or Beuves), Count of Ardennes, Boso was given the governance of Lombardy (876) by his brother-in-law Charles II the Bald, king of the West Franks (France), and received the title of duke. During the minorities of the West Frankish kings Louis III and Carloman, he convoked the bishops of Provence and had them proclaim him their king (Oct. 15, 879). Boso thereafter proceeded to expand his domains. The territory over which he usurped royal authority included not only Provence but many lands to the north, as far as Autun--an enlarged Burgundy.
"In succeeding years, especially 880-882, Boso lost many of the marginal northern lands to the French and German Carolingians, who were reestablishing their authority. He was succeeded by his son, Louis, who in 901 became the Frankish emperor Louis III."
Source: GEDCOM: Eileen McKinnon-Suggs, "Our Kingdom Come", 2003
Weis' "Ancestral Roots . . ." (141B:17).Stuart's "Royalty For Commoners" (343:39), citing ES I:57, Calls him
Boso II, Count of Vienne, King of Lower Burgundy.Boso was Count of Vienne and governor of Burgundy under theCarolingians. His wife, ERMENGARDE, felt that as she was the daughterof an emperor, she ought to be married to more than a mere count. Also, she considered herself as soverign of both Italy and Burgundy in her ownright. She persuaded Pope John VIII to crown Boso king of Provence. The years following the death of his father-in-law, KING LOUIS II of Italy without a male heir were a period of civil war between several rival claimants to the throne. From 875 to 877, CHARLES THE BALD, King of France (RIN 1620), was nominally also King of Italy. Boso was his main representative. Boso was an unsuccessful claimant in 879.
Source: GEDCOM: "Raúl Errázuriz Tagle"
Following the death of his brother-in-law Charles the Bald, Boso ofBurgundy declared himself King of Provence in 879. The area ofProvence then became called the Transjurane of Burgundy which
becamethe Kingdom of Arles.
When Charles the Bald took over Provence in 865 who gave theadministration of this region to his brother-in-law, Boso of Burgundy.