Complex sentence: The Qalawun Complex was built over the ruins of the Fatimd Palace of Cairo, with several halls in the Palace, it was sold to several people, where it was finally bought by the Sultan Qalawun in 1283 AD.
Split into simpler sentences: The Qalawun Complex was built over the ruins of the Fatimid Palace of Cairo, with several halls in the Palace. It was sold to several people until it was finally bought by the Sultan Qalawun in 1283 AD.