The Expansion of the Roman Catholic Church in Southeastern Macedonia and Southwestern Thrace and the Roots of the Conflict between the Latin Archbishop William of Philippi (William of Rouen) and Despotes Alexios Slav (Sthlabos)

The paper elucidates the preconditions and causes of the fatal conflict between the Latin Archbishop of Philippi William of Rouen and Despotes Alexios Slav (Sthlabos) in 1217 in the context of the Roman Catholic Church expanding into Southeastern Macedonia and Southwestern Thrace in the previous years. It also sheds light on the murder of the Catholic prelate. It importantly uncovers the specific and hitherto unknown circumstances associated with how Despotes Alexios Slav – a Bulgarian ruler of the Rhodope Mountains, the Philippopolis area, and Eastern Macedonia region, as well as a longtime loyal vassal of the Latin Empire of Constantinople – detached from the latter, and depicts his political reorientation toward an alliance with the neo-Byzantine state of Epirus. At the same time, it reveals Despotes Alexios Slav not only as a zealous defender of his own political interests in the region of Eastern and Southeastern Macedonia, and Southwestern Thrace, but also as a patron, benefactor, and defender of Orthodoxy in the lands under his control. 

Keywords: Despotes Alexios Slav (Sthlabos); Archbishop William of Philippi (William of Rouen); Archbishop Arnulf of Serres; Pope Innocent III; Pope Honorius III; Emperor Henry of Flanders; The Latin Empire of Constantinople; The Kingdom of Thessaloniki; The Roman Catholic Church; Eastern and Southeastern Macedonia, and Southwestern Thrace; Rhodope Mountains