Endowments (waqf) played a significant role in the prevalence of religious and charitable buildings in Egypt and Syria during Ayyubid and Mamluk periods. Endowment inscriptions were commonly used in Syria—almost on façades and entrances—to protect the endowed buildings from the robbing, damaging, or falsifying of their title deeds.   This paper investigates one of the remaining Ayyubid endowment inscriptions in Damascus dating back to AH 586/1190 CE. The text is written in seven lines on a rectangular stone slab, with the dimensions 80 cm x 120 cm, above the main entrance of the eastern façade of Shihab al-Din Mosque in Kafr Batna, Ghouta, Damascus.   The endowment is owned by the descendants of Muhammad Shihab el-Din: Abu al-Maali, Shihab and their sister. The inscriptions document two endowments: one is Shihab al-Din's mosque and mausoleum and the other an ongoing charity (sadqah jariah) on behalf of Bint Muhammad Bin Shihab al-Din's soul.   This research highlights the importance of these kinds of inscriptions in Syria, conditions that lead to their prevalence, and their role in endowments. The inscription text is represented in a comprehensive descriptive study accompanied with an analytical study of the inscription's form and content, covering all letters, words, titles, epithets, and  architectural terms used. In addition, the study highlights the main artistic aspects of the inscription, such as dotting and repeating some words, or focusing on specific phrases in conformity with the endowment's main objectives. The paper also compares this inscription to other Ayyubid and Mamluk inscriptions in Egypt and Syria.