Joseph had made his mind to divorce her informally, till the Angel of the Lord came in his dream and told him about the Lords will. The Lords Angel also told him that they must name the baby "Jesus". Mary gave birth to a son, and they named him Jesus. The baby was born through the Holy Spirit and hence Jesus was born Sin less. Mary and hence Jesus were descendents of David.
At the time of Jesus' birth Roman Emperor Caesar Augustus issued orders for the census. When Joseph came to the Israeli town of Bethlehem for the census, Mary and Joseph could not find a place for them to stay, hence they took shelter in a cattle shed. And baby Jesus was born in this cattle shed.
At the time of the birth, there was a special star shining in the sky. Some astronomers discovered this, and reported it to Herod the King of Judea. He was disturbed by this news, several centuries ago their prophets had told about the coming of Jesus and these were recorded in their scriptures. Following the star three Kings, the Wise men and the Shepard came to see the baby.
Cribs are made in most of the houses or even in public places for this day. Crib competitions are also held by various organizations in this period. In the Crib it is shown that .... ' baby Jesus is born, his mother Mary and Joseph are sitting besides him, three kings have come with precious gifts to see the baby, an Angel telling the Shepard about the birth of Jesus Christ '. In short the incident at the time of his birth is displayed. Special Masses are held on this day. Cakes and Sweets are distributed on this day.