After the Muslim conquest of the Levant in the 630s, the local Christians were Arabized even though large numbers were ethnically Arabs of the Ghassanid clans.
Bethlehem's two largest Arab Christian clans trace their ancestry to the Ghassanids, including al-Farahiyyah and an-Najajreh.
The former have descended from the Ghassanids who migrated from Yemen and from the Wadi Musa area in present-day Jordan and an-Najajreh descend from Najran.
Another Bethlehem clan, al-Anatreh, also trace their ancestry to the Ghassanids.

The percentage of Christians in the town has been in a steady decline since the mid-twentieth century.
In 1947, Christians made up 85% of the population, but by 1998, the figure had declined to 40%.
In 2005, the mayor of Bethlehem, Victor Batarseh explained that "due to the stress, either physical or psychological, and the bad economic situation, many people are emigrating, either Christians or Muslims, but it is more apparent among Christians, because they already are a minority."
The Palestinian Authority is officially committed to equality for Christians, although there have been incidents of violence against them by the Preventive Security Service and militant factions.
In 2006, the Palestinian Centre for Research and Cultural Dialogue conducted a poll among the city's Christians according to which 90% said they had had Muslim friends, 73.3% agreed that the PNA treated Christian heritage in the city with respect and 78% attributed the exodus of Christians to the Israeli blockade.
The only mosque in the Old City is the Mosque of Omar, located in the Manger Square.
By 2016, the Christian population of Bethlehem had declined to only 16%.

A study by Pew Research Center concluded that the decline in the Arab Christian population of the area was partially a result of a lower birth rate among Christians than among Muslims, but also partially due to the fact that Christians were more likely to emigrate from the region than any other religious group.
Amon Ramnon, a researcher at the Jerusalem Institute for Policy Research, stated that the reason why more Christians were emigrating than Muslims is because it is easier for Arab Christians to integrate into western communities than for Arab Muslims, since many of them attend church-affiliated schools, where they are taught European languages.
A higher percentage of Christians in the region are urban-dwellers, which also makes it easier for them to emigrate and assimilate into western populations.
A statistical analysis of the Christian exodus cited lack of economic and educational opportunity, especially due to the Christians' middle-class status and higher education.
Since the Second Intifada, 10% of the Christian population have left the city.
However, it is likely that there are many other factors, most of which are shared with the Palestinian population as a whole.
After the Muslim conquest of the Levant in the 630s, the local Christians were Arabized even though large numbers were ethnically Arabs of the Ghassanid clans. Bethlehem's two largest Arab Christian clans trace their ancestry to the Ghassanids, including al-Farahiyyah and an-Najajreh. The former have descended from the Ghassanids who migrated from Yemen and from the Wadi Musa area in present-day Jordan and an-Najajreh descend from Najran. Another Bethlehem clan, al-Anatreh, also trace their ancestry to the Ghassanids.
The percentage of Christians in the town has been in a steady decline since the mid-twentieth century. In 1947, Christians made up 85% of the population, but by 1998, the figure had declined to 40%. In 2005, the mayor of Bethlehem, Victor Batarseh explained that "due to the stress, either physical or psychological, and the bad economic situation, many people are emigrating, either Christians or Muslims, but it is more apparent among Christians, because they already are a minority." The Palestinian Authority is officially committed to equality for Christians, although there have been incidents of violence against them by the Preventive Security Service and militant factions. In 2006, the Palestinian Centre for Research and Cultural Dialogue conducted a poll among the city's Christians according to which 90% said they had had Muslim friends, 73.3% agreed that the PNA treated Christian heritage in the city with respect and 78% attributed the exodus of Christians to the Israeli blockade. The only mosque in the Old City is the Mosque of Omar, located in the Manger Square. By 2016, the Christian population of Bethlehem had declined to only 16%.
A study by Pew Research Center concluded that the decline in the Arab Christian population of the area was partially a result of a lower birth rate among Christians than among Muslims, but also partially due to the fact that Christians were more likely to emigrate from the region than any other religious group. Amon Ramnon, a researcher at the Jerusalem Institute for Policy Research, stated that the reason why more Christians were emigrating than Muslims is because it is easier for Arab Christians to integrate into western communities than for Arab Muslims, since many of them attend church-affiliated schools, where they are taught European languages. A higher percentage of Christians in the region are urban-dwellers, which also makes it easier for them to emigrate and assimilate into western populations. A statistical analysis of the Christian exodus cited lack of economic and educational opportunity, especially due to the Christians' middle-class status and higher education. Since the Second Intifada, 10% of the Christian population have left the city. However, it is likely that there are many other factors, most of which are shared with the Palestinian population as a whole.
Bethlehem