Their fame, once known from Constantinople to Edinburgh, had lived on only in books about the medieval Crusades and the power plays of the Renaissance.

Moving between ancient Mesopotamia, the medieval Crusades, the Atlantic slave trade and innumerable other historical epochs, his 500-page study argues that although debt has always been the basis of human society, it is not the same thing as money.

He is considered one of the foremost historians of the Crusades in the United States, and was often called upon as a historical consultant after the events of September 11, to discuss the connections between Jihad, the medieval Crusades and modern Islamic terrorism.

During the visit of Pope John Paul II to Syria in 2001, Bashar al-Assad requested an apology to Muslims for the medieval Crusades and criticised Israeli treatment of Palestinians.

Qutb wrote bitterly about European imperialism, which he regarded as nothing more than a continuation of the medieval Crusades against Islam.

Nor were the medieval Crusades, as some historians claim, merely an attempt by Christians to reconquer the formerly Christian-ruled, Christian holy land to which some historians disagree because the crusaders slaughtered Arab Christians too.

The 2004 PBS documentary Ancient Refuge in the Holy Land and the 2005 History Channel documentary Crusades: Crescent & the Cross focusing on the medieval Crusades were both narrated by him.

Money and explosives are transferred across the middle of the great Eurasian land mass in ways that Islamist terrorists see as a riposte to the medieval Crusades.

The Ninth Crusade, which is sometimes grouped with the Eighth Crusade, is commonly considered to be the last major medieval Crusade to the Holy Land.

LeBlanc created the hairstyle for Bardem's character in No Country for Old Men, drawing on the mop tops of the British warriors in the medieval Crusades as well as the haircuts of the 1960s for inspiration.