The waters of the bay were littered with floating wooden crosses. To each was nailed the decapitated corpse of a warrior who had died trying to defend the island. This was the gruesome sight which presented itself to Malta’s citizens in the last days of June 1565. After a month-long siege the fortress of St. Elmo had been obliterated by Muslim artillery and its 1,500 surviving inhabitants had been butchered. The incident has a horribly familiar ring to it. We recognise the fanatical nihilism of terrorists who justify their own most inhuman impulses by reference to the creation of a worldwide Islamic state from which everything not in accord with Sharia law would have been purged.

Historian Derek Wilson is speaking at the Telegraph Ways With Words Festival of Words and Ideas at Dartington Hall, in Devon, on 10th July.