Eventually, probably in 1372/73, John retired from public life altogether and entered a monastery, leaving Alexios as the ruler of Thessaly.
Around 1382, Alexios sought the protection of the Byzantine Empire, recognizing the suzerainty of the prince Manuel Palaiologos, who at the time governed Thessalonica as an appanage.
Alexios is lastly recorded in 1388, and must have died by c. 1390, when he was succeeded by his son (or perhaps brother), Manuel.
[1][3] It is recorded that in 1389, the "Caesar of Thessaly" sent aid to the ruler of Ioannina, Esau de' Buondelmonti against the Albanian tribes of Epirus, and that their joint forces scored a major victory over them, but it is unclear if by that date Alexios was still alive.
[4] Either he or, more plausibly, Manuel, was the grandfather of the mid-15th century Serbian ruler Mihailo Anđelović and the Ottoman Grand Vizier Mahmud Pasha Angelović.