The violence in Iraq is hastening the end of nearly 2,000 years of Christianity there as the few remaining faithful flee Islamic State militants, archbishops from Baghdad, Mosul and Kirkuk said on Wednesday. War and sectarian conflict have shrunk Iraq's Christian population to about 400,000 from 1.5 million before the U.S.-led invasion in 2003, and now even those who stayed are leaving for Turkey, Lebanon and western Europe, the prelates said on a visit to Brussels seeking European Union help to protect their flocks.