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was not recorded, and so it is impossible to know how many people
died. In general, contemporary commentators recorded only the
names of leading crusaders who were killed, and gave large rounded
estimates of the numbers of ordinary knights and other soldiers
who died. They usually did not mention non-warriors at all, except
in a sweeping and vague statement. The writers would sometimes
record, for example, that the crusaders had killed everyone in
a city, but they gave only round figures for the numbers of dead.
We may suspect that in fact they were boasting about how wonderful
their warriors were and what a fantastic victory they had won
(which they interpreted as a sign that God was on their side),
but that in fact many people had escaped.
Historians can attempt to identify individual crusaders who set off on crusade and did not return, but it is not possible to account for the many unknown people whose departure and death on campaign was not recorded by anyone. On the other hand, when we are trying to calculate how many people were killed by the crusaders, we can look at what happened after the crusade and try to draw some conclusions. For example, did land fall out of cultivation or did people continue to work it? If there were still people working the land then clearly not everyone had been killed, for although the crusaders tried to encourage colonists in the lands that they conquered, they were not very successful. In the Iberian Peninsula and in the Middle East the crusaders could not afford to kill the people who worked the land because then they would have no farmers to produce food. So it was usual to leave the ordinary workers alone, and to kill only the warriors.
On the problems of weighing up accounts of slaughter and of working out who died and who escaped, see also the answer to the question about how many people were killed when the first crusaders entered Jerusalem.