Shared heritage The states which made up Germany, like the countries which made up Britain shared a common Christian heritage – a mixture of Protestant and Roman Catholic churches. Though the depth of Christian self-understanding on the part of those individually engaging in the war is open to question, it is evident that the assumptions and social norms of most people in each of the countries were shaped by Christianity.
Intertwined monarchiesThe monarchies of both countries were formally Christian in ethos. There was inter-marriage between them and recent visits for celebrations. Not only were the British Monarch George V and the German Emperor Wilhelm  cousins (Wilhelm was the eldest grandson of Queen Victoria), they were Heads of their established national Churches. (In Britain, not until 1917 was the family name, via  Albert, of Saxe-Coburg-Gotha changed to that of the House of Windsor.)
Direct Ecumenical links.There were reciprocal links between several of the churches of the two countries and many personal friendships between individual clergy and theologians. The warmth of feeling towards Germany expressed by church leaders including the Archbishop of Canterbury in welcoming some 130 Protestant and RC clergy during an ecumenical exchange visit in 1908 is extraordinary (recorded in the official report: Peace and the Churches). This was equally true on the part of church leaders from Germany towards an equivalent British visiting group in 1909 (official report: Friendly Relations between Great Britain and Germany). All of this was formally endorsed by the creation in 1910-11 of The Associated Councils of Churches in the British and German Empires for Fostering Friendly Relations between the Two People.
Current symbols of friendly intimacy between Britain and Germany In June 1914, the annual Kiel Regatta, which had included a visit from four battleships of the British Navy, ended with the German Emperor inspecting the British flagship HMS King George V. He was wearing the uniform of a British Admiral and he was duly saluted by all the British ships hoisting flags in his recognition.