Bishop Shlemon Warduni,  the second most senior Chaldean in Iraq, arrives to lead Christmas mass at the Virgin Mary Chaldean Christian church  (Church of Our Lady of Sacred Heart) in the capital Baghdad on December 25, 2011. Iraq's dwindling Christian population marked Christmas with religious leaders calling for peace, days after attacks across Baghdad killed dozens and a political row raised sectarian tensions.  Warduni estimates that Iraq's Christian population, put at between 800,000 to 1.2 million before the 2003 US-led invasion that overthrew dictator Saddam Hussein, had halved since then.   AFP PHOTO/AHMAD AL-RUBAYE (Photo credit should read AHMAD AL-RUBAYE/AFP/Getty Images)