The southern remnant of Middle Francia's Burgundian/Provencal lands, proclaimed a kingdom by Boso of Provence in 879 (elected by regional nobles at Mantaille) and centered on the lower Rhone valley.
Reunited with the Transjurane Kingdom of (Upper) Burgundy in 933 under Rudolph II, forming the combined Kingdom of Burgundy/Arles.
No dedicated English-language monograph on this short-lived kingdom or on Boso of Provence was found on Open Library (only a 1911 German-language dissertation, 'Boso von Niederburgund'); this synthesis covers the 855/879 Carolingian succession that produced it.