As the attention of the world focused on Ukraine and Gaza, the Islamic State of Iraq and Syria (Isis) captured a third of Syria in addition to the quarter of Iraq it had seized in June. The frontiers of the new Caliphate declared by Isis on 29 June are expanding by the day and now cover an area larger than Great Britain and inhabited by at least six million people, a population larger than that of Denmark, Finland or Ireland. In a few weeks of fighting in Syria Isis has established itself as the dominant force in the Syrian opposition, routing the official al-Qaida affiliate, Jabhat al-Nusra, in the oil-rich province of Deir Ezzor and executing its local commander as he tried to flee. In northern Syria some five thousand Isis fighters are using tanks and artillery captured from the Iraqi army in Mosul to besiege half a million Kurds in their enclave at Kobani on the Turkish border. In central Syria, near Palmyra, Isis fought the Syrian army as it overran the al-Shaer gasfield, one of the largest in the country, in a surprise assault that left an estimated three hundred soldiers and civilians dead. Repeated government counter-attacks finally retook the gasfield but Isis still controls most of Syria’s oil and gas production. The Caliphate may be poor and isolated but its oil wells and control of crucial roads provide a steady income in addition to the plunder of war.