Jerusalem was extraordinary, overwhelming, baffling, a warren of streets, a stew of history. On the Temple Mount, the gold cap of the Dome of the Rock gleamed like the sun brought down to earth, and beside it the silvery al-Aqsa mosque was light, airy, a dream in stone. The Muslims called the Mount al-Haram ash-Sharif: the Noble Holy Place. The Muslims were relative newcomers to Jerusalem, compared to the Jews and the Christians, but even they had already been here centuries.

The city was full of churches, of course. Some of them, built by the crusader kings of Jerusalem, were quite modern, with ribbed vaults and pointed arches, and would have graced any city of western Christendom. Others were older, more squat and monumental. These were Roman, many of them built during the long centuries after the legions had left Britain. Thomas poked around these buildings, fascinated.

But as he talked and analysed and speculated, Saladin hardly spoke. To him, Thomas thought, history meant little. Jerusalem was nothing but an arena for the warfare he expected to dominate his life, as it had the lives of his ancestors since Robert, who had come here with the First Crusade that had swept through the Holy Land like a fiery wind.

The Christian states the crusaders planted here had survived three generations, until fortune threw up a great Muslim commander: a former vizier from Egypt, al-Malik al-Nasir Salah ed-Din Yusuf, known to the Christians as Saladin, who marched on Jerusalem. Even Richard the Lionheart was not strong enough to take back the holy city. Today Jerusalem was ruled under an agreement negotiated by the German emperor Frederick II, the nominal king of Jerusalem. The city had been left unfortified, and Muslims were allowed to remain; it was a shabby deal. Still, some of the old Christian families, like Joan’s, had crept back into the city which they had regarded as their home for generations.

So much for warfare. But, Thomas asked himself, what kind of people were these folk of the Outremer?

The boy Saladin was an ardent Christian, that was certain; here on the front line of Christendom you would expect a sharpening of the faith. But he looked more Saracen than English, with his flowing robes, his dark skin, and Thomas had heard him jabber Arabic phrases as easily as he spoke his stilted English. Thomas guessed that there had been a few infusions of Saracen blood into his line over the generations. Saladin’s deepest ancestry was English, but transplanted to the soil of Palestine for generations his kind had become something different, neither English nor Palestinian, something new in the world since the time of Robert.