The ancient ruins of Palmyra. Palmyra (or Tadmor in Arabic) dates back to the Neolithic period and was first mentioned in the second millennium BC as a caravan stop. It later came under the Seleucid Empire and then under the Roman Empire. In May 2015 Islamic State (IS) forces fighting the Syrian government of President Assad took control of the modern settlement of Tadmur and the historic site. There are fears that the priceless treasures could fall victim to IS's iconoclastic destruction that has seen museums and ancient sites across Syria and Iraq destroyed.