The Christosemitism project sets out to study the history of the Roman-Catholic and the Protestant repudiation of antisemitism - Christian anti-antisemitism - in Western Europe between 1945 and 2020. Western Christian communities have not merely changed their traditional approaches towards Jews, but, rather, anti-antisemitism became a core component of Christian self-understanding, and of the way in which Christianity is lived, practiced, navigated and polemicized in contemporary Europe. European Christian anti-antisemitism expresses itself in multiple ecclesial declarations, theological works, liturgical events, educational projects, and professional appointments. As such, Christian anti-antisemitism is inherently tied to the reconfiguration of Christianity in the late 20th and early 21st century, in the context of liberal secular society. Through the prism of the history of anti-antisemitism, Christosemitism seeks to transform our understanding of contemporary Western Christianity.