Al-Muallaq Mosque was built in 1758 by the Arab ruler of Acre, Zahir al-Umar. It was built in a courtyard on the site of a structure commissioned by the Crusaders and which later became the gate to the Genoaese quarter of the city. Up until 1746, the structure was used as a synagogue by Acre's Jewish residents, called the Ramchal Synagogue. The Jews still owned the building when Zahir chose to transform it into a mosque, but compensated them with a different building located in Acre's Jewish quarter. Leftover features of the synagogue include the niche for the Holy Ark and inscriptions in Hebrew.
The mosque is positioned along the edge of Acre's Old City market, situated between Khan al-Umdan and Khan al-Ifranj, and is risen over the street. From the outside, the main indicators of the mosque are its low-lying dome and the round base of its former minaret. The mosque's entrance is located beneath the original minaret's base. This minaret was demolished by the municipality of Acre in 1950, citing a public safety risk. The body of the mosque is mainly constituted by a large, square-shaped prayer hall, A triple-domed portico precedes the prayer hall's entrance. Beside the prayer hall is a smaller room that is currently used as a library. A stairway beneath a covered entryway leads into the courtyard.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.