World, Italy, Lombards, Beneventum, gold solidus c. 788-92 AD, Grimoald III with Charlemagne

Beneventum (modern-day Benevento, Italy) was the last of the Lombard states to remain independent, although Grimoald III was forced to submit to suzerainty under Charlemagne in 787, as evidenced by this issue which gives the name of both rulers. After 792, he again claimed total independence. 

Charlemagne's gold coinage from Francia and other Italian mints is excessively rare and largely held in museums; these coins of Beneventum, while rare, are known in significant enough numbers to be available to private collectors. 

BMC Vandals etc. p. 171, 3-5