Alcuin of York joined this ruler's court, and a biography of him was written by Einhard.
A forged history of this ruler was likely written to increase the popularity of the Carmine de Santiago; that work about this ruler was written by Archbishop Turpin. Belgian historian Henri Pirenne stated that this leader "would be inconceivable" without Muhammad. A biographer of this ruler supposedly eloped to Seligenstadt with this ruler's daughter, Emma, and took inspiration from Suetonius' The Twelve Caesars. Under the sponsorship of this ruler, the Historia Langobardorum was written by (*) Paul the Deacon. This ruler commissioned four books refuting the 2nd Council of Nicaea by Theodulf. Walafrid Strabo modified a biography of this ruler. Alcuin of York joined this ruler's court, and a biography of him was written by Einhard. For 10 points, name this Frankish ruler whose ambush in Roncevaux Pass provided the basis for the Song of Roland.
A forged history of this ruler was likely written to increase the popularity of the Carmine de Santiago; that work about this ruler was written by Archbishop Turpin.
Charlemagne [or Charles I; Charles the Great; prompt on partial answers]