There is no real unity in the geste of Doon de Mayence. The rebellious barons are connected by the poets with Doon by imaginary genealogical ties, and all are represented as in opposition to Charlemagne, though their adventures, insofar as they possess a historical basis, must generally be referred to earlier or later periods than the reign of the great emperor.
The general insolence of their attitude to the sovereign suggests that Charlemagne is here only a name for his weaker successors. The tradition of a traitorous family of Mayence, which was developed in Italy into a series of stories of criminals, appeared later than the Carolingian cycle, for an interpolator in the Chronicle of Fredegar states (iv. 87) that the army of Sigebert was betrayed from within its own ranks by men of Mayence in a battle fought with Radulf on the banks of the Unstrut in Thuringia.
The chief heroes of the poems which make up the geste of Doon de Mayence are Ogier the Dane, the four sons of Aymon, and Huon of Bordeaux. It is probable that Doon himself was one of the last personages to be clearly defined, and that the chanson de geste relating his exploits was drawn up partly with the view of supplying a suitable ancestor for the other heroes. The latter half of the poem, the story of Doon’s wars in Saxony, is perhaps based on historical events, but the earlier half, which is really a separate romance dealing with his romantic childhood, is obviously pure fiction and dates from the thirteenth century. Doon had twelve sons, of whom the most noteworthy are:
The history of these personages is given in Doon de Mayence, Gaufrey, the romances relating to Ogier, Aye d’Avignon, the fragmentary Doon de Nanteuil, Gui de Nanteuil, Tristan de Nanteuil, Parise la Duchesse, Maugis d’Aigremont, Vivien l’amachour de Monbranc, Renaus de Montauban or Les Quatre Fits Aymon, and Huon de Bordeaux.