Following the
capture of
Constantinople by the
Fourth Crusade in April 1204, the establishment of the
Latin Empire on the ruins of the
Byzantine Empire and the
treaty of partition of the latter's lands among the Crusader leaders, most of Greece was taken over relatively quickly by the Crusaders.
Boniface of Montferrat established the
Kingdom of Thessalonica in northern and eastern Greece, and gave fiefs to his followers in
Thessaly and
Central Greece. Further south, the
Peloponnese was conquered by
William of Champlitte and
Geoffrey I of Villehardouin, establishing the
Principality of Achaea, under Thessalonica's suzerainty. Only
Epirus remained in Greek hands, with
Michael I Komnenos Doukas establishing a
separate principality there. Boniface of Montferrat was killed fighting against the
Bulgarians in 1207, leaving his underage son
Demetrius on the throne. The powerful Lombard barons however, under the regent
Oberto II of Biandrate, opposed Demetrius and his mother
Margaret of Hungary, and preferred the throne to pass to Boniface's eldest son,
William VI. They also opposed the Latin Emperor,
Henry of Flanders, and demanded sovereignty over most of the European lands of the Byzantine Empire for Thessalonica. Henry succeeded in outmanoeuvring the Lombard barons and in January crowned Demetrius king, but Biandrate and the other Lombard barons launched a rebellion across the kingdom. Henry imprisoned Biandrate in
Serres and marched south through Thessaly, overcoming the barons' opposition at
Larissa. Henry treated the surrendered barons leniently, allowing them to keep their fiefs. But the rebellion was not yet quelled, as the barons of Central Greece and
Euboea still opposed the emperor. ==Parliament of Ravennika and aftermath==