His role in the fall of the Lombard kingdom was the subject of legendary embellishment a century later and in the chansons de geste he evolved into the figure of Ogier the Dane.
[6] In the late summer or early fall of 753, Autchar and Bishop Chrodegang were sent to Rome to escort Pope Stephen II back to Francia for negotiations with Pippin.
At Bolzano, on the return trip to Bavaria, Autchar subscribed as a witness to Tassilo's charter of foundation for Innichen Abbey.
The exiles, probably including other Carloman loyalists, initially stayed at the royal court in Pavia, where may have arrived as early as February 772.
According to the Liber pontificalis, when he had gotten as far as Viterbo, Pope Adrian I sent emissaries to warn that "neither he, nor any of the Lombards, nor Autchar the Frank either" should enter papal territory again on pain of excommunication.
According to the Liber pontificalis, Charlemagne led a small band of specially picked troops to Verona and "as soon as he got there, Autchar and Carloman's wife and sons immediately handed themselves over of their own free wills".
[17] If he was the same Autchar who founded Sankt Pölten after 791, he was probably also the commander, alongside Graman, of the victorious army against the Avars at the battle of the Ybbsfeld in 788.
Otkerus, as Notker spells his name, climbs the highest tower in Pavia with King Desiderius as the siege begins.
[19] Although the exchange with Desiderius is a piece of storytelling, Notker's description of Autchar as "a military expert and very well-acquainted with strategy and the composition of the siege trains" is likely accurate.