After negotiating with some Saxon nobles and obtaining hostages , he installs a number of garrisons .
Charlemagne devastates several major Saxon strongholds , and forces them to retreat beyond the Weser River .
After negotiating with some Saxon nobles and obtaining hostages , Charlemagne installs a number of garrisons .
Charlemagne devastates several major Saxon strongholds , and forces them to retreat beyond the Weser River .