Sahyun Castle, also known as Mons Peregrinus, is a medieval castle located in the Hama Governorate of Syria. It was built by the Crusaders in the early 12th century, and was strategically located on the top of a hill overlooking the surrounding landscape.

The castle was constructed by the Knights Hospitaller, who used it as a stronghold for their operations in the region. It was also used as a refuge for the local Christian population during times of war and conflict.

Sahyun Castle is considered to be one of the best-preserved Crusader castles in the Middle East, with its walls and towers still largely intact. The castle is also known for its impressive moat, which is cut into the solid rock of the hill on which the castle stands.

In the 13th century, the castle fell into the hands of the Muslim Ayyubid dynasty, who made some modifications to the structure. It later passed into the hands of the Mamluk Sultanate, who used it as a military base.

Today, Sahyun Castle is a popular tourist destination in Syria, attracting visitors from all over the world who come to marvel at its impressive architecture and learn about its rich history. Despite being damaged during the Syrian Civil War, the castle remains an important symbol of the country's cultural heritage.