Sorry for the late reply, but here it is:
The Ottoman Catholic minorities of Anatolia finally rise to arms under the leadership of Osman Bey Ghazi, a former Muslim who had recently converted to the Christian Catholic faith. With various wars, both foreign and civil, the Byzantine Empire is coming to an end. The Catholics under Osman now seek revenge on both Orthodox and Muslim nations. With the Crusaders destroyed, they now have their mind set on three specific cities: Constantinople, Jerusalem, and Mecca.
They decided to destroy their enemies, they would need assistance from the inside. The skills of Asymmetric Warfare was to be learned. To increase production in their temporary capital, a blacksmith was ordered to be built by the newly-crowned Ottoman King. Amazed at this new nation, cities around the capital joined the Ottoman Kingdom. Catholicism was spread to these regions, creating a mostly-unified Catholic state. The first ever sense the Romans to succeed at this.
The main cities of these newly-joined regions began establishing infrastructure. Roads connected these cities to give merchants and armies easy traveling across the land. Resources of these regions began to be harvested and mined. The stage was set for one of the greatest powers the middle east will ever see on its soil.
With King Osman Leading them, the Ottoman army arrived at the gates of Constantinople. The first truly great Ottoman city was within their grasp. The siege of Constantinople has begun.
Amazed by the new Catholic state, the remnants of the Crusaders, the Knights Hospitaller, arrived in Brusa to assist any and every war effort. Genoan merchants, finally with a safe place to trade, established shops in Canekkale. Infrastructure expanded in Ottoman territories as a result of these new helping hands. In response to the kindness of fellow Catholics, Osman decided to reform the government's legal and religious systems to be more dedicated to the state religion.
Envoys from the Mamluks, a military division that gained enough influence to succeed the Ayyubids, came. Though the state was Muslim, they were respectful to the growing Ottoman state. Orhan, the new King as Osman died 1824, signed a peace treaty.
Even though infrastructure was building nicely, religious minorities of Izmur, the most multi-religious city in the Ottoman Kingdom tried to rebel. Orhan let the local authorities find their own way to get things to settle down. Somehow, they managed to get the revolt to stop before too much was plundered. The men who succeeded in averting what could have potentially been a civil war were commended and sent to help capture Constantinople, where they became war heroes as well as civil heroes.
Back on the war-front, the last rounds from the trebuchet artillery force hit the Theodosian walls, destroying the defenses of the city. The trebuchet was then sent to attack the defense force of the city. Horsemen charged out, and though the trebuchets managed to destroy most of them before they reached the medieval artillery, they did damage to the weapons before being driven back. Now it was a battle of armies. Though the Ottomans lost their fair share of men, the city was finally taken. the Ottomans had just taken the city that has stood as the capital for three great Empires before it. The Ottomans would be the fourth to call it such.