DOON DE MAYENCE, a hero of romance, who gives his name to the third cycle of the Charlemagne romances, those dealing with the feudal revolts. There is no real unity in the geste of Doon de Mayence. The rebellious barons are connected by the trouveres with Doon by imaginary genealogical ties, and all are represented as in opposition to Charlemagne, though their adventures, in so far as they possess a historical basis, must gen erally be referred to earlier or later periods. 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, was, however, anterior to the Caro lingian cycle, for an interpolator in the chronicle of Fredegarius 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 (q.v.), the four sons of Aymon (see RENAUD), and Huon of Bordeaux (q.v.). 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 is obviously pure fiction and dates from the 13th century.