In 2023, a team from Inrap conducted excavations at the ancient mosque of Tsingoni in Mayotte. The work, supervised by the local municipality, focused on both the visible parts of the structure and what lay beneath the ground. The goal was to better understand the origins and development of this important building, which is a key part of the Mahorais cultural heritage. The first stage of the study has now concluded, with the submission of a detailed excavation report. The mosque of Tsingoni is the oldest known in Mayotte and was declared a Historic Monument in 2015. Archaeologists had already uncovered evidence of occupation dating back to the 13th century during a 2016 survey. This included the remains of an early stone mosque, a simple structure with a single room. Its walls were made from beach gravel, coral, and basalt—materials commonly used in similar mosques along the Swahili coast of East Africa. From the 16th century, Tsingoni began to grow significantly, becoming the capital of the Sultanate of Mayotte and separating from Anjouan. The mosque was then expanded and decorated with new additions, such as lateral wings and a southern wing. Massive pillars were placed on the foundations of the original structure, and a new mihrab (a niche indicating the direction of Mecca) was built in 1538, decorated with intricate interlacing patterns. Archaeologists also uncovered post holes in the prayer room, likely used to support scaffolding during the mosque’s expansion. The study of the building's masonry showed multiple stages of renovation, including traces of formwork used to shape the structure. Polychrome coatings in red, blue, and white were found beneath layers of paint on the mihrab. More recently, excavations revealed a trilobed niche containing fragments of printed paper, an iron nail, and other items—suggesting this was a votive deposit. The paper, identified as wood pulp from the 19th century, was carefully preserved and studied. The ink used was carbon black with traces of Mars red, a synthetic pigment from the 18th century. The fragments were found to be pages from the Quran (mushaf), likely placed as a ritual offering. This practice, known as ziara, reflects a blend of Islamic and local animist traditions in the region, influenced by earlier Western colonization. The excavation has revealed five major phases of construction, from the Middle Ages through to modern times. It highlights the earliest known stone mosque, dating back to the late 12th century, earlier than previously thought. This period marked the rise of power and the spread of Sunni Islam in the region. The findings contribute to broader research on the processes of Islamization and the development of local powers across the Swahili coast, Comoros, and Madagascar. The site provides valuable insights into how local communities adapted and incorporated architectural and religious models from different cultures. A public presentation of the findings was held during the JEP Conference by Justine Saadi, the excavation leader from Inrap, on Saturday, September 19, at 10:00 AM at the Place of the Ancient Mosque of Tsingoni, Mayotte. Following the conference, the Quran fragments will be displayed at the city hall.