The earliest date at which it can be proved that Charlemagne had the conquest of the Saxon districts in view is 776. Charlemagne's campaigns were intended mainly to punish the Saxons for their annual marauding expeditions to the Rhine. Charlemagne also vigorously pursued the conversion of the Saxons to Christianity, which involved the Frankish emperor in the suppression of the native religion and brutalities such as the execution of 4,500 Saxons at Verden in 782.