The Chaldeans are a Semitic people from southeastern Mesopotamia (now Iraq). The Chaldeans arrived in Mesopotamia from the Levant between the 11th and 9th centuries BC, and, from the late 10th century BC to the mid-6th century BC, they ruled over a state which briefly ruled over Babylon. The Chaldeans disappeared with the fall of Babylon to the Persians in 539 BC, but a new Chaldean community formed in Upper Mesopotamia during the 16th and 17th centuries as former Nestorian Christians who entered into communion with the Catholic Church in 1552. They lived in northern Iraq, southeast Turkey, and northeast Syria for centuries, but religious persecution forced them to emigrate to the West. In 2016, the Chaldean world population was almost 641,000 people.