Thrasco succeeded his father, and continued the warfare against the Saxons. An Engrian revolt followed in 796, but Charlemagne's personal presence and the aid of loyal Christian Saxons and Slavs (including Obotrites) immediately crushed it. Charlemagne then continued his goal to convert
Old Saxony into Christianity from paganism. The Frankish-Obotrite forces were led by Thrasco and
legatus Eburisus. According to
Einhard's chronicles, the Nordalbingians lost 4,000 soldiers and were forced to retreat. The battle finally ended the Nordalbingian resistance to Christianization. Charlemagne ordered further massacres, and deportations; their areas in
Holstein became sparsely populated and were given to the Obotrites. The Sorbs then ended their vassalage to the Franks and revolted, invading
Austrasia.
Charles the Younger launched a campaign against the
Slavs in
Bohemia in 805, and after killing Duke
Lecho of the Bohemians, Charles himself crossed the
Saale with his army and killed Sorbian princes
Miliduch and
Nussito, near modern-day
Weißenfels, in 806. The region was laid to waste, upon which the other Slavic chieftains submitted and gave hostages. In 808, Danish king
Gudfred, after building the
Danevirke (for the defence of a possible Frankish attack), crossed into Obotrite area at
Reric (modern
Wismar) and forced them to acknowledge him as their suzerain. The port was part of a strategic trade route, and Gudfred destroyed the town and forced the merchants to resettle at
Hedeby (in Danevirke). In 810, Thrasco was murdered by a vassal of Gudfred in Reric. ==Aftermath==