The study aims to deal with a mosque called the Great Mosque in the new city of Fez, located in the Moulay (Abdullah) neighborhood in Morocco, which was the first mosque built in the era of the Marinid state to be the royal mosque in the new city and for the Marinid Sultan (Abu Yusef Yaqoub bin Abdul Haq) in the year 677 AH/1278 AD) in order to attend his five prayers in it, and to sit in it with his entourage to consult in matters of his state, which led to it sometimes being called the Mosque of al-Mashur, and then this became the main royal mosque for the Marinid sultans, and thus it gained great interest from the sultans and rulers who They also followed that period, and this building was one of the largest mosques built in the era of the Marinid state, in addition to that it underwent many renovations and additions in later eras, and this mosque still maintains its historical value because it is the mosque that the current ruler of the state establishes to pray when he visits Medina New Fez. Perhaps the most important characteristic of this mosque is that it is one of the annexes of the royal palace of the new city, and it was built in the style of Marinid architecture, which was distinguished by being similar to the Latin letter T scheme, as it includes a courtyard surrounded by only three corridors, and the two side porticos were considered as corridors for the main iwan in the mosque It is the Iwan of the Qibla, to pass through it in the winter season when the rains fall, in addition to its inclusion of a mausoleum, the Jinzi Mosque and the Einza, which are considered one of the most important archaeological pieces remaining from the era of the Marinid state. At that time.