Thessalonica had never regained its power after…
1256 CE
Thessalonica had never regained its power after the battle of Klokotnitsa, in which the Bulgarian emperor Ivan Asen II defeated, captured, and later blinded Theodore Komnenos Doukas, the despotēs of Epirus.
His brother Manuel Komnenos Doukas had taken power in Thessalonica, while their nephew Michael II Komnenos Doukas took over Epirus.
Theodore, released in 1237, had overthrown his brother and set up his son John Komnenos Doukas as ruler of Thessalonica.
Michael II's relations with the Empire of Nicaea ensured his neutrality during the conflict in which John III Doukas Vatatzes had conquered Thessalonica and penetrated into northern Greece in 1244.
Theodore's younger son Demetrios Angelos Doukas had lost Thessalonica to Nicaea in 1246 and Michael had allied with the Latins against the Nicaeans.
John III had forced Michael to recognize him as emperor in 1248, however, and officially recognized him in turn as despotēs in Epirus.