Massacre and forced baptisms by the Crusaders of Volkmar, despite the opposition of Bishop Cosmas

The army of Volkmar, making its way to the East through Bohemia, halted at Prague. The Jews there were massacred and forcibly baptized, despite the opposition of Bishop Cosmas — the same who wrote the chronicle of the Czechs, in which the episode is recorded.

Cosmas, a cleric trained in law, deemed the forced baptisms null and the massacre criminal; he lacked the means to stop an armed force. Duke Bretislav was then in Poland.

Many survivors left Bohemia some years later, taking with them what they could; the duke had their belongings seized on the grounds that they derived them from the country. The community of Prague reformed nonetheless and became, over the centuries, one of the most enduring in Central Europe — its Old-New Synagogue and its old cemetery still bear witness to this.