IN THE EVE OF STALIN’S GREAT TERROR in 1935, the Jazz-Age globetrotter Richard Halliburton made a pit stop in Tbilisi, the capital of what was then the Soviet Republic of Georgia and a vibrant meeting place of East and West in the foothills of the Caucasus Mountains.

Halliburton had escaped from his state-appointed Intourist guides for long enough to score a massive scoop by interviewing the killer of the Romanov family, Peter Ermakov, in Siberia. The notes from that interview, he claimed, had to be sewn into the coat linings of friends and smuggled across the Soviet border.

While in Tbilisi, Halliburton heard a story whispered in the city’s basement taverns and tea rooms of an event that had taken place during the First World War. In his travelogue Seven League Boots, he writes:

In the spring of 1915, some months after Russia’s declaration of war against Turkey, a band of twelfth-century Crusaders, covered from head to foot in rusty chain armour and carrying shields and broadswords came riding on horseback down the main avenue [of Tbilisi]. People’s eyes almost popped out of their heads. Obviously this was no cinema company going on location. These were Crusaders — or their ghosts. The incredible troop clanked up to the governor’s palace. ‘Where’s the war?’ They asked. ‘We hear there’s a war’.

They had heard in April 1915 that there was a war. It had been declared in September 1914. The news took seven months to reach the last of the Crusaders.… [Legend] declares that this race came, 800 years ago, from Lorraine, more than 2,000 miles away. The argument is borne out by the fact that their chain