Military operations against the Latins

he successor of Theodore I to the imperial throne was his son-in-law John I Vatatzes. In the field of foreign policy, John carried on the work of the former emperor, his ultimate aim being the recovery of Constantinople, which was in Latin hands. Although John did not achieve this goal, he did manage to make Nicaea a powerful state, by successfully exploiting political developments during that period.

Immediately after his accession to the throne, John III was confronted with an uprising led by the brothers of Theodore I and assisted by the Latins, the aim of which was the usurpation of imperial power. John defeated the Western forces at Poimanenon in 1225 and the peace treaty that followed deprived them of all their acquisitions in Asia Minor, except for Nikomedeia and the coasts opposite Constantinople. At the same time, the Nicaean fleet recovered the islands of Lesbos, Samos, Chios, Ikaria and Kos, while, a little later, John forced Leo Gavalas of Rhodes into submission. After this, John undertook military operations on European territory. The Nicaean forces succeeded in taking several coastal cities and invading Adrianople (most probably in 1225), but they were repulsed by the forces of the emperor of Thessalonike, Theodore Doukas Angelos (1224-1230).

The failure of the Nicaean army at Adrianople obliged Vatatzes to turn to the East. A successful expedition against the Turks in Asia Minor (around 1225-31) secured the eastern borders of the country. But it was only after the termination of this expedition and the simultaneous defeat of Theodore Doukas at the hands of the Bulgarian tsar, John II Asen, at Klokotnica in the spring of 1230 - a defeat which rid Vatatzes, once and for all, of his Western rival - that the Emperor of Nicaea could finally take action against the Latins in Constantinople.

|Attempts to recover Constantinople| |Fall of the Empire of Thessalonike| |Relations between Nicaea and Epiros| |Diplomatic moves|