in 1236–37, aymon, baron of faucigny, made himself protector of the priory of chamonix despite the fact that the count of geneva had a prior right. the ensuing war, in which aymon's son-in-law, "le petit charlemagne", was captured by william's son rudolf, resulted in genevan defeat, for on 13 may 1237 william ii was forced to accept the judgement of peter's brother, amadeus iv, count of savoy, condemning him to an indemnity of 20,000 marks and the cession of the strategic castle arlod on the rhône near its confluence with the valserine, which commanded the approach to the lyonnais. the sum of 20,000 marks was beyond william's ability to pay and the value of the fortress he was compelled to give up too high. the count of geneva and peter continued to be at war intermittently for the next five years. in 1242 william and "le petit charlemagne" fought a final brief war for control of arlod. on 26 august, however, meeting his adversary "in front of arlod", he was forced to cede it.