In this study, the work titled Risale-i Akaid-i Diniyye, registered in the name of Abdurrahman b. Muhammad al-Aydıni, is introduced with its general features and evaluated in terms of its writing characteristics. No information about the author of the work, al-Aydıni, could be found in the sources. According to the information in Risale-i Akaid-i Diniyye, he wrote his work on behalf of Sinan Bey, the chamberlain of İsa Bey, son of İshak Bey, in 844 AH / 1460 AD. Risale-i Akaid-i Diniyye is a prose book of aqaid that briefly mentions the theological provisions of the Islamic religion. The work, which is included in a mecmua numbered 673 in Yusuf Aga Library in Konya, is written in unmoved form, has 35 folios, and there is no date of its printing. In the work, which shows the spelling and language features of Old Turkey Turkish, Islamic sects and their views on aqaid are included. The views of Ahl al-Sunnah and Jamaat sect are defended and the views of other sects are also included in the work. While information about the concepts of the science of aqaid is given under the titles of muqaddimah and ıstılah, the different views of the sects on the issues of belief are included under the titles of issue, fayide and question-answer. In addition, at the end of the work, there is a chapter on the life of the Prophet Muhammad (PBUH) under the title of chapter. The work is very important in terms of showing that works on religious subjects were written in Turkish in the XVth century. Besides, it has a wide vocabulary related to religion, belief and aqa'id. The aim of this study is to introduce the prose aqaid treatise titled Risale-i Akaid-i Diniyye, to reveal the content of the work and the writing characteristics of the period in which it was written with examples.

Risale-i Akaid-i Diniyye, Aydıni, Old Turkey Turkish, Akaid, 15th Century.