Between 132–135 the city was occupied by the Romans after its capture during the Bar Kokhba Revolt. Its Jewish residents were expelled by the military orders of Hadrian. While ruling Bethlehem, the Romans built a shrine to the mythical Greek cult figure Adonis on the site of the Nativity. A church was erected in 326, when Helena, the mother of the first Byzantine emperor Constantine, visited Bethlehem.

During the Samaritan revolt of 529, Bethlehem was sacked and its walls and the Church of the Nativity destroyed, but they were soon rebuilt on the orders of the Emperor Justinian I. In 614, the Persian Sassanid Empire invaded Palestine and captured Bethlehem. A story recounted in later sources holds that they refrained from destroying the church on seeing the magi depicted in Persian clothing in a mosaic.

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