Two names stand out in the wealth of young talent which forged the networks which came together in what has come to be called the ecumenical movement, John R. Mott (1865–1955) and his contemporary Nathan Söderblom (1866–1931). For his fellow American Robert Schneider, Mott was ‘undoubtedly the most famous Protestant ecumenist of the early twentieth century’. To his fellow Swede Bengt Sundkler, Söderblom provided the spark of innovation in 1919–20 which was ‘the beginnings in embryo of what later became the ecumenical movement in its modern form’. The purpose of this paper is to consider their contributions in the period from 1890 to 1922, and the overlap and divergences of their roles in the movements contributing to ecumenical thinking and action. Amongst those disparate though sometimes overlapping strands were the concerns of foreign missions, students and peace. A subsidiary theme is that of mischief-making, sometimes out of ignorance, sometimes by design of the press.