"The Sultanate of Rûm would fall by one of the most unexpected circumstances; an exiled prince would return to claim the throne, but having converted to Christiany and siding with the Byzantines."
An excerpt from Aquitanian Historian de Toulon's book "Pax Komnenia" detailing the Eastern Empire's renewal. This line in particular denotes the start of the Second Phase of the Empire's reconquest, similarly paralleling the simultaneously occurring "Reconquista" where the Christian Kingdoms of Iberia restored Hispania under the banner of Christ.
Truly the 13th Century was a period of renewal as opposed to total collapse, as it had initially seemed to be under the ill-fated Fourth Crusade. After a period of misrule, the Komnenian dynasty's future seemed precarious, but thanks to the swift action of Emperor Manuel II Komnenos who deposed his insane father, the Empire was in capable hands once again.
With sane and rational policy now emanating from Constantinople, the Empire began a concerted effort at consolidation and then expansion in the name of securing more defensible territory to protect its existing core. This of course isn't suprising as this policy of "pre-emptive Self-Defense" was not new to the Romans who had adopted such tactics during the Early days of the Republic.
And with their stunning victories many Turks were impressed by the martial spirit of the Romans with many captured soldiers starting to convert to Christianity. It was the same with the Sultan Mesud who after barely escaping his brother's ruthless purge of their family, he fled Iconium dressed as a beggar before being found by a group of Roman expeditionaries. In his poor condition, the young Sultan had fallen sick, and taking pity upon him, a local priest prayed over him for his recovery which took place that night after he broke his fever.
Changed by his experience, he told his captors who he was and was brought before Emperor Alexios III Komnenos. Alexios initially delighted at having a new bargaining piece to use against the Sultan, was shocked by how Mesud threw himself at the Ecumenical Patriarch's feet begging to learn more about Christ. From there he was baptized and lived his life as a Christian, even marrying a Roman woman. But despite his new cushy life, Mesud he never forgot the treachery of his youngest brother, who massacred almost the entirety of the Royal family in a quest to eliminate threats to his power.
With Roman assistance, Sultan Mesud overthrew his treacherous brother and much to the shock of the Turks of Rum, declared himself a Christian Sultan, something which caused a violent backlash against him leading to an armed rebellion which Mesud had crushed against all odds. But despite his the outcome of the battle, he knew it was a pyrrhic one as both his strength and that of his enemies were depleted which left them at the mercy of the Romans. Had Mesud's wounds not taken its toll, we might have seen a Christian Turkish state emerge similar to how the Bulgars emerged in the Balkans, but that was not the fate of Rum, as its namesake used the death of Mesud as a pretext to outright conquer it completing the reconquest of Anatolia.
For his valiance in battle, and dedication to Christ, Sultan Mesud was cannonized as a so-called "Warrior Saint," a patron of soldiers and those persecuted in the name of Christ, and is venerated as a Saint. Tales of his deeds reached Rome which impressed the Holy See that it too began venerating him as a Saint in the West. This event funnily enough marked the start of the gradual reconciliation between East and West leading to the Reunion of the Two Churches following the Conclusion of the War of Sicilian Succession.
"I and my House are usurpers you say? The people, princes, and deputies of the Reichstag have acclaimed me as German Emperor. As far as you Hohenzollerns are concerned, should you even attempt to contest this, you might get lynched by a mob which not even I would be powerless to stop as thanks your actions, the Sacred Fatherland has been cleaved in two. I'd let you rule your birthright, the Kingdom of Prussia, but that title will most likely be titular for now, as Prussia has been conquered by those godless Bolsheviks."