In the 13th century, Genghis Khan and his Mongol hordes wreaked devastation in Central Asia, China, Russia, the Middle East and Eastern Europe.

A BBC television documentary compared Islamic State to the Mongol hordes because they have at least one thing in common: the dissemination of fear – through cruelty and excessive force – as an instrument of war.

The documentary traced the rise of Islamic State. It showed that the threat from this criminal, extortionist, well-funded jihadist organisation is very serious. The documentary ended with foreboding: unless the indoctrination by Islamic State is eradicated at its roots, it will continue to grow and the future will be “dark”.

In The Lessons of History (published in 1968), historian Will Durant wrote: “If history supports any theology, this would be a dualism like the Zoroastrian or Manichaean: a good spirit and an evil spirit battling for control of the universe and men's souls.

“These faiths and Christianity assured their followers that the good spirit would win in the end; but of this consummation history offers no guarantee.

“Nature and history do not agree with our conceptions of good and bad. They define good as that which survives, and bad as that which goes under.

“The universe has no prejudice in favour of Christ as against Genghis Khan.”

John Guillaumier

St Julian’s