The Syrian and Russian governments have hailed their recapture of the ancient oasis city of Palmyra from Islamic State, ending a 10-month ordeal that saw the destruction of some of the historic site’s most famed monuments. The battle for the city is the latest in a string of defeats for Isis, now in retreat across Syria and Iraq, where it once controlled vast tracts of territory: nearly half of Syria and the desert plains of Nineveh and most of Anbar in Iraq.