The Crusader Citadel of Mousaylaha is built on a confined gigantic rock near Nahr-El Jawz River with abrupt steep surfaces emerging from the center of a field bordered by mountains and hills. The site was occupied from the time of the Roman rule between 13th and 17th century.
The current castle was constructed by Emir Fakhreddine ll during the 17th century in order to oversee and patrol the route between Tripoli and Beirut. The walls are built from a combination of tiny sandstone blocks from the close-by coast and limestone rock, developed into a thickness of approximately 2 meters. Due to the destructive consequences of time, weather and nature, the only remnants of an earlier architecture presumably constructed for a similar defensive reason are large blocks of limestone.
The layout of the fortress is made up of two divisions each built in a separate time phase. Visitors may arrive at the fort after passing through a narrow pathway and a small staircase that cuts through the northern side of the base of the structure. A small stage rests ahead of the low arched main gate, safeguarded by two escape clauses with a small cavity in the rooftop overhead the main entrance. The primary gate leads to a small lobby which then allows access to a triangular lawn which in turn opens to a hallway that is small, three feet wide and leads to the west tower archery room.
The south side of the lawn consists of two vaulted bays that are built within an isolated structural segment of the fortress over vast arched chambers that previously served as warehouses. It is important to mention that this part of the architectural structure has a small chamber directed towards the Qibla (the outlook of Mecca, which was used as a prayer room for accommodated companions).
Moreover, there is a room on the first floor which can be reached through an internal staircase, this is the most equipped and barricaded part of the fortress because its location is ideally strategic with regard to monitoring the entry of Nahr-El-Jawz valley. The site has been renovated and taken care off, installed with metal handrails, landscaping and water drainage systems to avoid water leaks into the citadel. These works are funded by the United States Agency for International Development in collaboration with the Lebanese Ministry of Tourism and the Ministry of Culture - Directorate General of Antiquities.