Yassıçimen War: According to the records in El Evamirü'l Ala'iye fi'l-Umuri'l-Ala'iye by Ibn Bibi

The XIII. th Century Anatolian History Signifies an interesting period with the existence of several political changes. One of the points which makes the changes interesting is that, during the reign of Sultan Alaeddin Keykubad I, both the Anatolian Seljuk Empire and Anatolia, in its known history, experienced their richest and most glorious period, economically and politically. On the other hand, the very same century was also a period of political chaos and economic inconsistency caused by the Mongol invasion. İn other words, Anatolia experienced both the rise and the fall, economically and politically, during the century. These changes in Anatolia effected the neighbourhood; the Causasus and the Middle East.One of the elements that shaped this period is the relations between the Anatolian Seljuk Empire and Khwarezmians, especially the rivalry between Sultan Alaeddin Keykubad I and Sultan Celaleddin Harezmşah. Khwarezmians came to the Caucasus and the east of Anatolia under the pressure of Mongols, and became neighbours with Seljuks. Sultan Alaeddin Keykubad I who was a great strategist, decided to make and agreement with Sultan Celaleddin Harezmşah to become allies against Mongols. However, relations, which were friendly in the beginning, were destroyed by both Sultan Celaleddin Harezmşah?s besieging Ahlat and the provacation by `meliks? who were holding the position of local ruler. Eventually, Yassıçimen War broke aut between these two countries. The war reduced the power and the energy of both sides who actually must have been allies. İn the end Khwarezmians Empire was collapsed, which helped Mongols arrive in the Anatolia, and with the arrival of Mongols, Political and economic stability in Anatolia was disappeared.One of the most significant sources about the period is the book called El-Evamirü?l Alaiye fi?l-Umuri?l Alaiye by İbn Bibi. İn this study, Yassıçimen War was discussed in the light of the book mentioned above.