he most important achievement of the foreign policy of Andronikos III in the eyes of his people was the incorporation of the small Greek states of Epiros and Thessaly into the Byzantine Empire. These had already broken away from the Empire since 1204, and had fought resolutely to remain independent when the Empire was restored in 1261.

After the death, in 1333, of the lord of Thessaly, Stephen Gabrielopoulos Melissenos, Andronikos III re-established his authority over the area as far south as the borders of the Catalans of Athens. At the same time, he ousted the despotes of Epiros, John Orsini, who was making territorial claims over the western part of Thessaly, and subjugated the Albanians living in that region, who had been independent until then. He also took advantage of the internal strife in Epiros to seize the region temporarily in 1337 and to occupy it definitively in 1340, when, at the head of a small military force, along with Kantakouzenos, he repressed a rebellion that had broken out in the area against Palaiologos.

However, the two small states did not remain long under Byzantine domination. Soon, both Epiros and Thessaly succumbed to the conquering fury of the Serbs (1348).