The Church of the Nativity is the oldest church in the world. After Christianity became the official religion of the Eastern Roman state during the reign of Emperor Constantine in 324 AD, his mother, Queen Helena, ordered in 335 AD to build the Church of the Nativity in the same place where Jesus Christ, peace be upon him, was born in the city of Bethlehem. The construction of the church was completed in 339 AD, and it was built in the basaltic style, an architectural style adapted from the Roman temples. The church includes what is known as the Cave of the Nativity of Christ and white marble floors. The cave is decorated with fourteen silver lamps and many images of saints. The church is a large religious complex representing different Christian denominations. There is the Orthodox monastery in the southeast, the Armenian monastery in the southwest, and the Franciscan monastery in the north, which was built in 1347 AD for the followers of the Franciscan sect.