The junction of the Rhine and Danube was undertaken only for the service of the Pannonian war, (Gaillard, Vie de Charlemagne, tom. ii. p. 312-315). The canal, which would have been only two leagues in length, and of which some traces are still extant in Swabia, was interrupted by excessive rains, military avocations, and superstitious fears (Schaepflin, Hist. de l'Academie des Inscriptions, tom. xviii. p. 256. Molimina fluviorum, etc., jungendorum, p. 59-62.).