About that ultimatum: as CNN reports, the Islamic State in Iraq and Syria, or ISIS, has distributed letters to Christian leaders in the Iraqi city of Mosul giving them the option to “accept Islam, pay extra taxes to Islamic Sharia courts or face ‘death by the sword.'”

The message added that ISIS leader Abu Bakr al-Baghdadi has agreed to allow them (Christians who do not agree to convert or pay extra taxes) to leave the embattled city by noon Saturday (5 a.m. ET). After that, the message said, “the only option is the sword.”

Anyone who doubts the sincerity of ISIS should note the markings painted on the homes of Christians and other non-Muslims.