Sultan Kalim was dead, or a prisoner of Persia. The Ottoman Empire, which had withstood so much, was utterly broken.
Tasan Kemal despaired as his fellow Turks resigned themselves to the sight of Persian troops in Constantinople. The Ottomans were dead, but the Turks were still very much alive.
Kemal had been in charge of the defenses of Edirne, until it collapsed into anarchy. He refused to fight his own people as they vied for the control of a dead nation. In the chaotic weeks after the fall of his city, Kemal had travelled around the wreak of his people's homeland, gathering his own supporters along with his remaining army. But he would not continue the war against Persia like the desperate fools who remained in control. He would do what was good for Turkey.
After 3 months, he had gathered enough support. He had fought off the shards of the former Ottoman army, and was possibly the only power remaining. His gamble would either pay off or end his life, and the life of Turkey.
For Ardashir IV, Shah of Persia
My name is Tasan Kemal. I am, as far as I know, the last Ottoman who wields any power at all. I have a force of several thousand men behind me, but I do not wish to continue the fight with your nation.
What I wish for is the survival of the nation of Turkey. I will have my people stop their struggle against Persia forever, if Turkey, heart of the old Ottoman Empire, is to remain independent. We wish to keep Anatolia plus Istanbul and Edirne. The rest of our dead Empire, you may do with as you wish.
I hope most deeply that you will appreciate this offer.
Sincerely,
Tasan Kemal
Note: Roughly modern Turkey's borders.