A quasi-independent Frankish sub-kingdom/duchy south of the Loire, ruled in practice as its own realm by Duke Odo the Great and his successors from Toulouse. Odo defeated an Umayyad army at the Battle of Toulouse (721) and later allied with Charles Martel to help repel the Umayyads at Tours (732), while resisting full Frankish overlordship for most of the 8th century under his son Hunald and grandson Waifer.
Crushed by Charlemagne's campaigns of 768-769 following Duke Waifer's assassination; absorbed into the Frankish realm and later revived as a nominal Carolingian sub-kingdom (781) and, after 843, a West Frankish duchy.
The atlas holds 4 border frames for Duchy of Aquitaine (independent duchy, 7th-8th c.) — the shape you scrub through changes in 670 · 711 · 721 · 751.
FALLBACK (broad survey): no dedicated English-language monograph specifically on the independent 7th-8th c. duchy verified on Open Library (Aquitaine-titled works there are almost all about the later, 12th-c. Eleanor of Aquitaine). James's standard history of the Franks covers the Aquitanian dukes' revolt against, and eventual conquest by, the Carolingians in detail.