This lecture will be about the mosque of Ahmad ibn Tulun, a Turk who founded a dynasty that briefly ruled Egypt between the 9th and early 10th centuries. This period marked the spark of a splendid city with some great architectural projects. Amongst them was the famous mosque which still bears Ibn Tulun’s name and is the oldest existing mosque in Egypt. It has always been considered an architectural masterpiece, and has gone through a long series of changes. The lecture will investigate architectural projects and rebuildings which took place since its foundation. We will attempt to understand how these various designs appeared in their original state. A series of visual reconstructions will be discussed, based on the records provided by medieval historians.