IN 1995 some 200,000 Serbs were ethnically cleansed from Croatia. Oh, no, actually, they fled. During the second world war Serbian royalist “Chetniks” were heroes—or were they villains? Balkan history is complicated, but there is widespread agreement on one thing. Every nation knows what is right and how everyone else is wrong. As one Serbian historian puts it: “There is one truth, just as there is one God.”

When Yugoslavia fell apart in the 1990s the question of who did what in 1389 or 1944 played a vital part in the propaganda used to whip up hatred. Balkan children are still being taught wildly varying versions of history with no idea that others view the same events differently. Since 1999, however, a group of historians from across the region has been working to help teachers gain a broader perspective. So far, they have brought out four books of source materials covering the period up to 1945.

Last month at a meeting in Belgrade of the Centre for Democracy and Reconciliation in Southeast Europe, which runs the project from Thessaloniki, the historians planned the next stage: the cold war and events since 1989. The challenge is huge. Still, by 2014 an estimated 500,000 students may have benefited.

None of this can come too soon. In Bosnia there are war memorials standing only a few hundred metres from each other, dedicated to young men who almost certainly went to school together shortly before they began killing one another in the 1990s. Bosniak children today are taught that their forces succeeded in defending Sarajevo during the siege of 1992-95. But the Serbs, who besieged it, maintain that they successfully defended themselves against being overrun by the city’s Muslim hordes.

Kosovo’s history books are full of Albanian heroes and play down inconvenient truths. Serbian and Croatian books seem to have evolved out of this first phase of nationalist euphoria, but still do not offer a balanced version of events. Change takes time. Nenad Sebek, the project’s director, tells funders that if they want results next year they should take their money elsewhere. “We are hoping for results in 10 to 20 years.”