The philological study of the Islamic literary heritage of Ethiopia has been a shallowly approached field of research. The former kingdom of Ğimma, despite its rich Islamic history, remains almost completely unstudied in respect to philology. The purpose of this research is to present a description and catalogue of manuscripts at the Seddeqiyyu mosque in Ğimma zone, Sokorru woreda. It has 6 chapters. The first chapter gives an introduction to the whole research. The second chapter deals with the history of Islamization of the five Gibe kingdoms. The third chapter presents the biography of Šayḫ Musid al-Dīn Seddeqi, who established the Seddeqiyyu mosque and wrote almost all of the manuscripts to be studied here. In the fourth chapter the kinds of manuscripts of Seddeqiyyu mosque are introduced and typologized; particular emphasis is given to the “strange” texts and pictures which were invented by the Šayḫ. I identified 17 kinds of pictures and 6 kinds of “strange” texts. The fifth chapter is the main theme of this thesis. It deals with cataloguing the manuscripts of Seddeqa. 52 manuscripts are catalogued under four main groups. In the last chapter (six), conclusions and recommendations are given. The method used to catalogue these manuscripts is based on the one suggested by Yusuf Ziyya. However there are modifications I introduced to it, in order to make the criteria fit the nature of the manuscripts. Prior to this research the Seddeqiyyu collection was completely unstudied; it is currently kept in bad condition which makes it vulnerable to damage. I hope this study will open the gate for further studies on the collection and on previously unstudied genres of Islamic manuscripts in Ethiopia.