Bethlehem was administered by the British Mandate from 1920 until 1948. In the United Nations General Assembly's 1947 resolution to partition Palestine, Bethlehem was included in the special international enclave of Jerusalem to be administered by the United Nations.

Jordan annexed the city during the 1948 Arab-Israeli War. Many refugees from areas captured by Israeli forces in 1947–48 fled to the Bethlehem area, primarily settling in the what became the official refugee camps of 'Azza (Beit Jibrin) and 'Aida in the north and Dheisheh in the south. The influx of refugees significantly transformed Bethlehem's Christian majority into a Muslim one.

Jordan retained control of the city until the Six-Day War in 1967, when Bethlehem was occupied by Israel, along with the rest of the West Bank. On December 21, 1995, Israeli troops withdrew from Bethlehem, and three days later the city came under the complete administration and military control of the Palestinian National Authority in conformance with the Interim Agreement on the West Bank and the Gaza Strip in 1995.

Source: http://en.wikipedia.org/wiki/Bethlehem