Before Bosporus extended a helping hand to Constantine, who was Despotate, his 36-year-old Brother-in-law was frantically dealing with the succession in Mistras, Morea.
Due to the unexpected death of his elder brother, the Empire's established plans were almost completely shattered.
Further negotiations between the Roman Curia and Constantinople regarding a Crusade and church unity naturally came to nothing, and although the Ottoman had not yet shown signs of taking over Constantinople, their fleet in the Sea of Marmara still showed no signs of leaving.
The Italian commercial Republics, led by Venice, watched from the sidelines, waiting for an opportunity.
Under these circumstances, even with his brother John's prior designation and some support from the citizens of Constantinople, Constantine found it difficult to secure the imperial throne.
Moreover, as of now, his other brother, Theodore, and his younger brother, Dimitrios, had both stepped forward to claim the throne.
Crucially, his active promotion of John VIII's decision regarding church unity had, ironically, undermined his popularity among the citizens of Constantinople.
In addition to the above situation, foreign attitudes towards him were not optimistic.
Regarding the death of John VIII, Ottoman Sultan Murad II merely sent a simple message of condolence to Constantinople and did not overtly interfere with Constantinople, but the messenger specifically warned the Empire before leaving, demanding that the newly appointed Basileus immediately submit to Edirne, and as mentioned, the Sultan's fleet patrolling the Sea of Marmara had not decreased at all.
And when Constantine sought help from commercial powers like Venice, these merchants, waiting to be bought, all stated that they would only act after the outcome in Morea was clear, which greatly angered Constantine.
In this almost desperate situation, to Constantine's extreme surprise, his Brother-in-law, Bosporus Caesar Manuel, took the initiative to send a secret envoy to contact him in the middle of this month, asking if he needed assistance from Bosporus.
Constantine, deeply knowledgeable in politics, knew that there was never such a thing as a free lunch or a generous gift in this world, even if the other party was his Brother-in-law.
But at the same time, their shared identity as Romans naturally made him trust Manuel, and coupled with his current need for a force strong enough to influence Constantinople's internal affairs, after discussing with trusted aides like Sfrantzis, he ultimately chose to cautiously accept the olive branch extended by Bosporus, agreeing to its cooperation request.
After the other party expressed agreement, his Brother-in-law officially sent several political figures, including Chancellor Serenus, by boat to Morea in secret later that month, to discuss with him how to place the Despotate on the throne of Constantinople.
"Holy Father above, long time no see, Caesar." Under the cover of night, Serenus, having concealed his identity and draped in a black robe, greeted his old acquaintance and former superior, Constantine, with his usual warmth.
"No more small talk, let's discuss how to deal with the current situation." Constantine sighed and secretly invited these people from Bosporus into his residence in Mistras.
After confirming that no outsiders knew their true identities, Constantine and his trusted aides present all breathed a sigh of relief.
At this point, the Moria Despotate took the opportunity to ask, "You and your Caesar understand the situation, right?"
To the Despotate's question, those asked all nodded in affirmation.
In just half a month, the Empire's situation had seen new developments: during this time, Constantine, relying on his prestige and cunning, successfully brought his brother Thomas to his side, but his brother Theodore still stubbornly refused to acknowledge his right of succession, and his brother Dimitrios had caused chaos in Constantinople for quite some time, even threatening to bring the Ottoman into the city, causing widespread unrest and grievances.
"Caesar." At this point, Serenus, as the representative of Bosporus, had unilaterally changed his respectful address for Constantine, "Based on the discussions between Caesar and me in Trabzon, your becoming the sole heir to the Empire is actually not difficult: firstly, you are the most prestigious and capable among the late Emperor's brothers, and secondly, your competitors, apart from Prince Theodore, are not to be worried about."
"So, have you and Manuel in Trabzon figured out how to make Brother Theodore withdraw?" Constantine extended his left hand and pinched his brow.
"More or less, Caesar," Serenus bowed in greeting, directly sharing with him the idea his Caesar had proposed before arriving, "Please take action, after all, you are the true ruler of Morea."
"But this will certainly carry the risk of civil war…" Seeing this, Sfrantzis couldn't help but exclaim.
Before he finished speaking, he was interrupted by Serenus, "That's why, Caesar, action is needed precisely to avoid civil war.
Trust your prestige in Morea; how can Theodore, who was parachuted onto the peninsula by the late Emperor, compare to you, who has cultivated Peloponnese for decades!"
Constantine neither directly responded nor overtly rejected Serenus's words, but instead lowered his head, lost in thought.
After a long time, he finally raised his head again, his face ashen, and paused stiffly…
At the end of this month, Constantine personally led his personal guards in a night attack on the residence of his co-ruler, his brother Theodore, disarming him.
That same night, under Constantine's armed coercion, Theodore was forced to relinquish his claim to the throne and accept his brother's temporary "protection."
In exchange, Constantine promised to grant him his private domain of Selymbria upon his ascension to the throne.
Thus, his most threatening rival for the throne was resolved, leaving Constantine with only the problem of how to return to Constantinople.
Just as he was preparing to sell commercial interests to the Latins in exchange for their fleet support, Serenus merely smiled faintly, stating that Bosporus had already prepared the ships for him, "Please wait a few days, Caesar; Caesar will be arriving soon."
Although Constantine had doubts about whether his Brother-in-law could break through the Ottoman naval blockade, given the situation, he had no choice but to trust him for the time being.
As it turned out, on the very first day of the New Year in 1441, several ships flying the pure black double-headed eagle flag of Bosporus truly arrived at the port of Morea.
And the leader of these ships was indeed his Brother-in-law, Bosporus Caesar Manuel.
While admiring and being surprised by his Brother-in-law, Constantine felt even more apprehension: what exactly did his Brother-in-law want by helping him so wholeheartedly?