Jizya.

This is coolbert:

ISIL demanding under duress that the Christians residing within the realm of the Caliph now pay the jizya. That tax "protected people" living under Islamic rule are required to pay.

Thanks to Jungle Trader and the BBC:

"Iraq"

"Iraqi Christians are fleeing Mosul after Islamist militants threatened to kill them unless they converted to Islam or paid a 'protection tax.'"

"A statement issued by the Islamic State in Iraq and Syria (ISIS) was read out at the city's mosques."

"It called on Christians to comply by midday on Saturday or face death if they did not leave the northern city."

coolbert.