them to rise up against the "Latin dogs". However, he had only won a Pyrrhic victory, because his best troopshis Latin mercenariesperished in the battlefield. Emperor Henry led his army across the Bosporus and routed Theodore's troops on the Rhyndakos River on 15October 1211. Henry captured Nymphaion and Pergamon. In a circular letter sent to the European monarchs early in 1212, he boasted of having subjugated the Greeks as far as the Seljuq frontier, save the garrisons of some fortresses. Henry had to end his military campaign because he did not have enough troops to garrison the captured fortresses. The two emperors made peace between 1212 and 1214 The peace confirmed the Latins' possession of the Troad region. The Latins also seized some strategically important Bithynian fortresses, taking control of the roads between the northern and southern territories of Theodore's realm. Theodore adopted an intensive fortification program. New fortresses were built, and the old fortresses' walls were restored. He also urged local officials to settle colonists around the new forts, granting arable lands to them. Theodore quickly recovered from his defeat. Taking advantage of a conflict between the Latin Empire and Serbia, Theodore and Sultan KaykausI invaded the Empire of Trebizond simultaneously in 1214. Theodore forced David Komnenos to abandon Heraclea Pontica on the Black Sea. Whether he conquered eastern Paphlagonia during this campaign, or only years later, is unclear. His conquest of the region put a narrow strip of land along the Black Sea coast under Nicaean control, and thus removed the emperors of Trebizond from the competition for Constantinople. Consolidation The Latin clerics wanted to compel the Orthodox population of Constantinople to adopt the Catholic liturgy and to pay the tithe, but they resisted. Pope InnocentIII sent Cardinal Pelagius as his legate to Constantinople in 1213 to discipline the Orthodox population for their resistance. Pelagius closed Orthodox churches and ordered the imprisonment of the resistant monks, but the Greeks did not give in and many of them fled to Nicaea. The Greek aristocrats approached Emperor Henry, asking him either to stop the persecution of Orthodoxy or to allow them to move to Nicaea. Henry capitulated and ordered the re-opening of Orthodox churches in Constantinople. Pelagius entered into negotiations with Theodore about a possible Church union at Heraclea Pontica, but their discussions proved inconclusive. Michael I Komnenos Doukas was assassinated in late 1214 or in 1215. Theodore Komnenos Doukas,