This book has two underlying themes: the Crusader period, which is the bit of history and archaeology I have chosen to spend a career studying, and the notion of repetition in history. The first theme is fairly straightforward—the Crusader period is a phase of history, easily defined. The second is more complex, for it is a human perception, not so much a fact as a feeling, and consequently enigmatic, and perhaps dubious, but certainly fascinating.

Does history indeed repeat itself? Mark Twain is said to have suggested an alternative: “History doesn't repeat itself, but it often rhymes.” Whether the attribution is correct (it has never been substantiated), this certainly Twain-like statement contains, as does any decent witticism, a subtle truth. For what is a rhyme? Not a repetition of the same word with the same meaning, but rather the following of one word by another that merely sounds the same. In a similar manner, what appears to be the repetition of a historical event is generally not that at all. Human history is old enough for there to be very little that is entirely new. If we take the earliest known use of stone tools by hominins at the end of the Pleistocene period, that is around 3.3 million years ago, to be the beginning of human history, we can appreciate that it would be remarkable indeed if a precursor could not be found for virtually any historical occurrence.

It seems that we are quick to grasp at the idea of repetition, perhaps because what is new is unknown, and what is unknown is frightening. When it landed upon us early in 2020, the covid–19 pandemic was immediately compared to the fourteenth-century Black Plague, and the Spanish Flu of 1918–1920. The comparison was perhaps a mildly comforting one, for although those pandemics decimated populations in many parts of the world, humanity made it through. And there was reassurance in the fact that with modern medical knowledge and technology we are today so much better equipped to face such disasters. There is comfort in comparison. And so, we say, “history has repeated itself,” and hold up examples like the attacks on Pearl Harbor and 9/11. And let's not get bogged down by the many details that challenge these comparisons.