Recently a member of the House of Lords that Israel “is not going to be there forever in its present form.”Whatever Baroness Jenny Tonge meant by these astonishingly ill-chosen words is not clear. It seems highly unlikely that Tonge was trying to make a profound point about the passage of time and the meaning of history – not least since this is not the first time that she has let her veil slip to show profoundly negative views about Israel.The writer is director of the Centre for Byzantine Research at Oxford University and author of The First Crusade: The Call from the East, which will be published next month by Harvard University Press.Ironically, though, there are good reasons to be grateful for the furor generated in Britain by the dark mutterings of a ranting politician. For one thing, it brings into sharp relief the fact that the precariousness of Israel’s present and future are taken seriously far beyond her borders. There is a realization that misguided comments need to be shot down, that it is unacceptable to even suggest that there may come a day when the odds stack up so high that fate takes what one senior British politician evidently thinks is its inevitable course.To the historian of the Middle Ages, the image of Israel being surrounded by an ocean of troubles and hostilities was a familiar one. After the Christian conquest of Jerusalem in 1099, the Crusaders agonized over how to hold the city and the other towns and territories that they had conquered as they crossed Asia Minor and Syria on their way to the Holy City.As with the foundation of modern Israel, there was a recognition from the outset that the state had to be anchored, in the first instance, on a powerful military, able to deal with threats that could be modest and local, but equally, could have the backing of some of the rulers of the medieval world – in this case, the sultans of Egypt and Baghdad respectively. There were moments of peace and moments of crisis, but the Christian rulers understood clearly that they needed manpower, training and discipline to survive whatever might be thrown at them.They recognized, too, that they needed to work hard to build long-term, longdistance alliances with their core supporters: the religious community, epitomized by the pope, was carefully cultivated, its own ambitions bound closely to those defending the Holy Land; the knighthood of Europe were fed tales of daring, bravery and glory by well-dragooned schools of chroniclers and writers; merchants from places like Venice, Genoa and Pisa were lured with trade concessions, designed to whet commercial appetites with the promises of rich rewards.None of this was accidental. The rulers of Jerusalem were acutely aware of their vulnerability, and worked tirelessly to present a positive image of themselves that resonated far from home. The Crusader lands became known as those across the sea – or Outremer. The kingdom of Jerusalem became known as a state whose existence was of central importance to Christian identity; its future understood as requiring support and vigilance to ensure its survival.The ground that had been so carefully laid did, of course, produce exactly the sort of results that were intended. Wave after wave of military expedition made for the Holy Land in the 12th and 13th centuries – to say nothing of the individuals who traveled there in a personal capacity either on pilgrimage or to serve with one of the great military orders, such as the Templars and Hospitallers.The Crusades were if nothing else testimony to the clarity of the message that was repeatedly reinforced that the survival of the Kingdom of Jerusalem (to paraphrase Baroness Tonge), might not be there forever in its present form. But where things went wrong for the Crusaders was not in the long-distance messaging to core supporters, but in the muddling of that message among its neighbors and near-neighbors.The capture of Jerusalem by the knights of the First Crusade owed a great deal to the fractured state of the Muslim world at the end of the eleventh century. Fatimid Egypt was at loggerheads with Sunni Baghdad, with regular military conflict between the two. The weak grip on power of the Seljuk sultan in particular provided opportunities for individual emirs to build power bases for themselves at the sultan’s expense, thereby both weakening him and distracting his attention.This free-for-all worked favorably for the Christian knights who for decades had to face strings of enemies, rather than a united block.This was swiftly recognized by the early Crusaders, who were smart enough to realize that the key to survival was to build alliances and play a skillful diplomatic game: today’s enemies could be tomorrow’s friends, and vice-versa. There was a recognition, too, that while Christian rhetoric worked well with an audience far removed from the scene, this had to be tuned down closer to home, where the practical realities of day-to-day life lent themselves better to tolerance and co-operation than to religious hatred.So after the bloodied frenzy that followed the capture of Jerusalem, it was not long before the minorities in the Crusader states found themselves enjoying legal protection, especially in the cities. Muslim travelers, Jewish merchants, Armenian pilgrims and anyone in between, found an environment that could be described as cosmopolitan and even enlightened.But this in turn was a cause of problems for new arrivals to the east, who were incredulous at the generous way in which so-called enemies of Christ (which could include rather a large basket of Christian “heretics” as well as Muslims and Jews) were treated. In due course, this led to a hardening of the expression of what the Crusader states meant not only internationally but nationally too. And this brought disastrous consequences.For one thing, it lined up the Kingdom of Jerusalem as a lightning rod for all opposition. It was central to Saladin’s uniting of the Islamic world, which led to his own capture of Jerusalem in 1187.It prompted the fractured Muslim world, in other words, to set aside its differences and to unite against a single target.If there is a lesson to be learnt from the Middle Ages, it is that the deftness of touch is not an easy thing to develop, and it even less easy to keep hold of. The mistake of the Crusaders was to allow themselves to be convinced of their own future, and to lose sight of the fact that it was the day-to-day realities of local alliances – the patchwork of potential friends and potential enemies – on which their survival rested. Baroness Tonge and her comments will doubtless be lost in the winds of history; but it is important to remember why she must be wrong.