In the summer of 1242, a Mongol force invaded the Latin Empire of Constantinople. This force, a detachment of the army under Qadan then devastating Bulgaria, entered the empire from the north. It was met by the Emperor Baldwin II, who was victorious in a first encounter but was subsequently defeated. The encounters probably took place in Thrace, but little can be said about them owing to the paucity of sources. Subsequent relations between Baldwin and the Mongol khans have been taken as evidence by some that Baldwin was captured and forced to make submission to the Mongols and pay tribute. Together with the major Mongol invasion of Anatolia the following year (1243), the Mongol defeat of Baldwin precipitated a power shift in the Aegean world.