Answer: Through their actions they contributed to fulfill the prophecy of Christ's coming.
Explanation: When the arrival of the Lord Jesus Christ comes, according to Christian terminology, it is thought of his first arrival, that is, his birth in Bethlehem and the preaching and healing the sick, in general, his work for which he came. His first arrival was when Israel and Judah were under the authority of Rome, an integral part of the Roman Empire. Also, according to the Christian belief, the coming of Christ, that is, the birth, life, and work on earth and death, are prophesied by many prophets of the Old Testament. According to these prophecies, Christ had to be born in Bethlehem not far from Jerusalem. As his parents lived in the distant Galilee, it was necessary something to happen which would fulfill the Old Testament prophecy. Thus, the Roman authorities are completely unaware of the significance of what will happen, they have ordered a population census. According to Jewish laws, the family originates from the place where the wife originated. Thus St. Mary and Joseph went on a journey to Bethlehem where she was originally, to enrol in the population census. As Mary was in a blessed state, she, as a result of the order of the Roman authorities, went to Bethlehem together with Joseph, and there she gave a birth to her son, Jesus Christ. Due to the great migration of people these days due to the census, all guest houses were full, so St. Mary and Joseph did not find the place, although Mary was in pain just before the birth. Thus Mary gave birth to Christ in the Bethlehem cave, just as it was foretold in the Old Testament. In those years, the Roman authorities unconsciously made many things that contributed to fulfill the prophecy concerning the life of the dead of Christ. For example, according to Roman laws, he was accused of being a criminal, and crucified, which was the Roman way of death, and was crucified among two other criminals, just as it is foretold in the Old Testament.
My opinion, when it comes to the coming of Christ, should take into account the eschatological character of a suitable environment and setting for his coming. Often, according to the Christian belief in God Promise, things happen in a way that is not predictable, and often by those who are not aware of their actions, and in fact contribute to this suitable setting, even if they were enemies.