the Chronicle of the Morea claims that Alexios left Michael as his lieutenant in the west. From these references some earlier scholars erroneously inferred that Michael received the title of despotes from Alexios. Lucien Stiernon, followed by Varzos, places the ransoming of Alexios in 1206/7. Loenertz on the other hand considers it a result of Michael's rapprochement with the Latins and places it in 1210, when the interests of the Latin Empire in curbing the growing power of Nicaea coincided with Michael's intention to ransom Alexios. Territorial expansion Michael seized the opportunity of Henry's focus on his planned campaign against Nicaea to attack Thessalonica. At the head of Latin mercenaries, he captured the constable of the Kingdom of Thessalonica and baron of Domokos, the Lombard Amé Buffa, and a hundred of his companions. He is alleged to have been excessively cruel to his prisoners, killing or whipping many of them, while Buffa, his confessor, and three other nobles were crucified. Michael's army proceeded to capture several fortresses and kill the Latin garrisons, including priests. Enraged, Henry sped to Thessalonica's aid, covering the distance from Constantinople in only twelve days. Michael in the meantime had allied himself with the Bulgarian ruler Strez, but they were defeated by Henry. It is possible that during this campaign, Henry was assisted by his vassals from Achaea, thereby explaining the reference in the Pope's correspondence of Achaean barons fighting against Michael, rather than assuming an Epirote expedition to the Peloponnese. The Latin Emperor wrested lands from both allies, but was forced to cut short his campaign and return to Constantinople, which was being threatened by the Bulgarian emperor Boril. Henry left Thessalonica in the charge of his brother Eustace and of Berthold of Katzenelnbogen, who then defeated another invasion by Strez, supported with troops from his brother Boril. Disquieted by the Bulgarian attacks on Thessalonica, Michael switched sides and joined the Latins in defeating the Bulgarians at Pelagonia. It is commonly assumed that during these conflicts, Michael terminated his vassalage to the Latin Empire; historian Philip Van Tricht however points out that there are no sources for this, and that this vassalage may have survived until 1217, when Michael's brother Theodore captured Latin Emperor Peter II of Courtenay near Dyrrhachium. Sometime between 1210 and 1214, according to the Chronicle of Galaxeidi, Michael came into conflict with the Latin Lord of Salona, Thomas I d'Autremencourt. When