As outlined by Oskar Halecki, the king's friends were largely recruited from the higher clergy and the Jesuits, who violated the 1573 Warsaw Confederation guaranteeing religious freedoms in Poland and Lithuania. As persecution loomed, political dissidents grouped and formed factions which called for adherence to the laws of the Confederation. Zamoyski joined the dissidents, and, when Sigismund failed to prevent mob violence directed against non-Catholics in Vilnius and Kraków in 1591, he summoned several conventions that "demanded the guarantees of security". Sigismund yielded to their demands, however, he forbade any future conventions which could destabilize the state. The prohibition did not have a lasting effect, and gatherings of dissidents continued in the following year.