[3] The mosque was built on the site of a former Crusader suburb near the Castle of Saint-Gilles (Tripoli Citadel), and has been mistaken for a repurposed Christian church by medieval travelers like al-Nabulsi,[5] and modern historians.

The church fell in disrepair following the massive earthquakes in 1170 and 1201; and as a result of the Mamluk sultan al-Manṣur Qalawun's siege of the city.

[7] Although the main entrance and minaret tower originated from a previous Christian structure, the mosque’s core elements—including its courtyard, arcades, fountain, and prayer hall are distinctly Islamic.

[9] Inscriptions in the mosque reveal that Qalawun's sons, Sultans al-Ashraf Khalil and al-Nasir Muhammad, were responsible for its construction in 1294 and the addition of the courtyard arcades in 1314, respectively.

[22] While its facade is relatively simple, the mosque is easily recognized by its prominent minaret and main northern gate, which are the only remains of the Christian church that existed on the site.

[3][4] Some scholars hold that the preexisting church was converted into a mosque with only minor Mamluk modifications, rather than being largely new construction; these views, however, are not widely accepted and are primarily based on outdated 19th-century Orientalist scholarship.

[23][24] Crusader craftsmanship is especially visible in the main entrance's design and ornamentation: This rectangular door is framed by a series of arches featuring alternating plain and zigzag stone moldings, which rest on two slender white marble colonnettes and four narrow wall segments.

In contrast, identical rosettes appear in Western architecture from the twelfth and thirteenth centuries, particularly in Crusader structures in Syria and Palestine.

These remnants from classical times appear to serve no practical or decorative purpose, similar to the two columns in front of Taynal's mosque and the Madrasa Saqraqiyya.

[28] It is divided into two aisles by six large piers, creating fourteen areas—thirteen covered by simple cross-vaults and the area in front of the mihrab topped by a small dome.

Although Arab historical records do not detail its distinctive characteristics, Western scholars have debated its unusual form since the 19th century.

Our master, the sultan, the king, the victorious, the just, the learned, the warrior, the triumphant, Nasir al Dunya wa l-Din Muhammad ibn Qala'un—may God sustain his reign—ordered these arcades to complete the blessed mosque, during the governorship of His Excellency Kustay al Nasiri, governor of Tripoli, may God grant him victory, under the supervision of Badr al Din Muhammad, son of Abu Bakr, inspector of flourishing diwans, may God lengthen his favor.

[3] The inscription reads: The humble servant of God, Qaratay, son of Abdallah al-Nasiri, ordered the construction of this blessed minbar.

The work was entrusted to Bakthuwan, son of Abdallah al-Shahabi, may God accept his efforts, in the month of Dhu al-Qadah, in the year 726 A.H.[d][3]A hair from the beard of the Prophet Muhammad is stored in the Mansouri Great Mosque.

The gift was presented in recognition of the loyalty of the Tripoli residents to the Ottoman Empire and was sent after the restoration of the Hamidy Mosque.

The relic, is considered one of the most valuable Islamic religious items in Lebanon and is traditionally visited on the last Friday of Ramadan and on the Prophet's birthday.