In December 1917 the British occupied Jerusalem and in few years established a Mandate to rule Palestine. During the First World War British policy makers made several contradicting promises to different actors in relation to the Middle East, the most dramatic to the Zionist movement with the Balfour Declaration promising the establishment of a Jewish National Home in Palestine. When the Balfour Declaration became public knowledge in late 1917 the attitude of local Arab Christians towards the Jews changed, as they felt threatened by Jewish immigration. This paper aims to show how the war had a major impact on the local Christian communities through the renegotiation of local alliances and on the de-marginalisation of the Christians, who subsequently became an active part of the emerging Arab nationalist movement. Local Christian notables in Jerusalem joined their Muslim counterparts in political, cultural and literary associations which opposed Jewish immigration. One of the main problems of these associations was the political vision of their Muslim members concerning the future of Palestine. Some local Muslim leaders encouraged Palestinian Christians to convert to Islam, as some Muslim leaders viewed Christian faith closely intertwined with European interests in the region and therefore corrupted. This paper argues religions were not transformed in their doctrines, but allowed some exchanges due to the contingency of the situation and political reasons. The zenith of this renegotiation of alliances took place in April 1920 when in occasion of the Nebi Musa celebrations, an Islamic religious festival whose purpose was to create a bond between various parts of country, riots broke out. Several were the outcomes of the riots, the most important a change in the perception of identity from religious to national. In this paper I will also argue that violence and trauma experienced in the region were embedded into political ideologies which 'inevitably' came to include seeds of violence. Due to the trauma of the Balfour Declaration and the violent struggle that emerged between Zionists and Arabs, violence became part of the local political vocabulary marking permanently the local identities of Jerusalem and a major shift from the Ottoman era.