The great general Sabotai led the attack. He split his forces into three, making diversionary thrusts to north and south while Sabotai himself led the main body of his forces across the Hungarian plain. Thus Sabotai controlled forces separated by hundreds of miles and by mountain ranges; there had been nothing like this coordination and control since the legions. And the forces of the Hungarian King Bela broke before these savage horsemen, their leathery dress strange, their horses small, fast and muscular.

Sabotai set up his yurts on the plain of northern Europe, and, in the autumn of 1241, prepared to overwinter before his next push west.

He was only a few days’ ride from Vienna, along the Danube. No Christian army had even slowed the Mongol advance, let alone halted it. Now it was a dagger held over the heart of Europe, a world empire preparing to overwhelm the petty, squabbling states of Christendom.

And yet Pope Innocent IV tried to deal with the Mongols. Even as the horses of Sabotai grazed east of Vienna, Philip of Marseilles was attached to a party of clerics and knights despatched to the court of Ogodai, son of Genghis Khan.

Many Christians had applauded as the Mongol attacks thrust into the soft belly of Islam. There were even hopeful rumours that some of the Mongols were Christians, adherents of a heretical sect called Nestorians who clung to an obscure argument about the separation of the divine and human nature of Christ. And there was a popular legend of a figure called Prester John, said to be descended from one of the magi who attended the birth of Christ, a Christian ruler of a vast kingdom in the east. So in the Pope’s counsels there was hope that the Mongols could be turned into allies against Islam, the ultimate foe.

Thus Philip and his party came to the strange capital of the khans, deep in their Asian homeland. This was a ‘city’ of nomads, a town of tents, each laden with pointless heaps of booty. And yet in this place they found embassies from across the known world and beyond. The Mongols’ destruction was terrible, but the unity they had imposed connected empires which had had little knowledge of each other since antiquity.

But Philip found that Ogodai, a clever, impulsive, hard-drinking man, was no Christian, no Prester John. In fact only a few Mongols were Nestorians; the rest adhered to a kind of primitive animism. And besides the Mongols waged war not for religion but for the conquest itself. To Ogodai even the Pope was no more than the weak leader of a rabble of petty states that would, in due course, be conquered, reduced and assimilated, and that was that. The Pope’s embassy failed.