A question about Constantine Palaiologos’ position at the imperial court

While working on Palaiologos Interlude, I came across something that made me wonder about Manuel II’s plans for his sons.

In 1417, Thomas was sent to the Morea while he was still a child. At the time, Constantine was only thirteen, and Demetrios was around ten. Yet Constantine remained in Constantinople rather than being sent to a provincial appanage.

This becomes even more interesting a few years later. Around 1422–1423, Manuel attempted to arrange an appanage for Demetrios on Lemnos, and Demetrios subsequently left Constantinople and went to Hungary. By the time John VIII left for the west in 1423, Constantine was therefore the only one of the younger imperial princes remaining in Constantinople who could take on responsibility for the city.

This raises a question for me: why was Constantine not sent to the Morea in the same way as Thomas, or given an island appanage such as Lemnos before Demetrios? Why was he instead kept in Constantinople and eventually appointed despot and regent there?

Could this suggest that Manuel II, perhaps together with John, had already decided at an early stage that Constantine should remain at the imperial court and assist John in governing the capital?

Sphrantzes later makes it clear that John particularly favored Constantine as his successor. Of course, that later preference does not necessarily mean that such a plan existed as early as 1417. Still, I wonder whether John’s later trust in Constantine was the continuation of a relationship and political role that had already begun to develop much earlier.

At this point, I would consider this only a hypothesis. The surviving sources do not, as far as I know, explicitly state that Manuel II had made such a plan for Constantine in 1417. But the different arrangements made for his sons make me wonder whether Constantine’s position at the center of the empire was more deliberate than it might first appear.