Inter-religious dialogue between Jews and Christians started in the 1940s, notably with the establishment of the International Council of Christians and Jews in Switzerland in 1947. The WJC has managed to establish good relations with the Catholic Church, especially since the Second Vatican Council and the Declaration "Nostra aetate" in 1965. Progress, however, is slow with regard to the Orthodox and Protestant Churches, which according to the WJC is mainly due to the decentralized nature of these churches and certain political issues related to the Middle East conflict.