This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Nachmanides, known by the acronym Ramban and born Moses ben Nachman in Girona in Catalonia, was compelled by King James I of Aragon in 1263 to take part in a public debate against Pablo Christiani, a Christian apostate from Judaism who argued that the Talmud itself testified to Jesus as messiah. The king granted Nachmanides an unusual guarantee of free speech for the debate, a documented royal concession rather than the constrained conditions such disputations usually imposed on the Jewish participant.
Nachmanides used that guarantee to rebut Christiani's claim point by point, and his own written account of the exchange, known as the Disputation of Barcelona, survives as a firsthand record rather than a summary compiled by someone else afterward. That the losing side of a royally staged religious debate produced its own detailed written rebuttal, preserved and read long after the event itself, distinguishes the Barcelona disputation from disputations whose record survives only through the account of the victors.
The survival of Nachmanides's own account of a debate he was compelled to enter, conducted under a free speech guarantee that did not shield him from the consequences that followed it, marks the Disputation of Barcelona as a documented case where the participant most at risk left the fullest surviving record of what was actually said.