sentences:  He sabotaged the rebels' boats in an attempt to drown them in the Rhone, but Guntram Boso reached Avignon, where Mummolus was staying, and besieged it.At the siege of Avignon, Mummolus displayed great tactical knowledge, diverting water from the river to a moat and digging holes in the bed of the moat to make it impossible to cross for the besieging force.Guntram's nephew, Childebert II, sent down an army which relieved Avignon and rescued Mummolus.