Timothy Flanders, writing about the twentieth-century movement toward unity between the Oriental and Eastern Orthodox Churches (who split over Christological disagreements after the Council of Chalcedon in 451), says that Protestant models of ecumenism paved the way:
It was within the WCC that two visionaries from each church met and began to collaborate—Nikos Nissiotis of the Ecumenical Patriarchate and Paul Verghese of the Malankara Indian Orthodox Church (later Metropolitan Paulos Mar Gregorios of Delhi). This work with the WCC helped galvanize the Orthodox to meet together at Rhodes in 1961—and also invite the Miaphysites. In 1963, when the WCC Faith & Order Commission met, Swiss Reformed Protestant Lukas Vischer began working closely with Nissiotis and Verghese to eventually organize the first formal Orthodox-Miaphysite consultation in 1964, in which the bulk of the division was overcome in matter of days.
Virtually as soon as the two church families managed to come into contrastive dialogue with each other in this century, it was realize that physis . . . was being used in different ways in our different churches.
In matter of days a division and misunderstanding that had lasted nearly fifteen hundred years—almost sixty generations!—was viewed in an entirely new and promising way, almost resolved then and there. And this was due in large part to the encouragement, sponsorship, and support of Protestant Christians through the WCC. Moreover, can not the Protestant openness to diversity in doctrine (no doubt to a fault at other times) be seen as a strength in the midst of intransigent myopia holding tenaciously to old prejudices? Indeed, this very cooperation with Protestants has helped the Orthodox rediscover their own tradition more fully. A more mature understanding of the Church canons, for instance, has been brought to bear on mainstream Orthodox theology.
Orthodox Christians have often been divided on the WCC, many seeing it with suspicion and hostility. The Special Commission on Orthodox Participation in the WCC was created in 1998 in an attempt to assuage Orthodox concerns about ecclesiology, social and ethical issues, interconfessional prayer, and the WCC’s structure and decision-making process. Nearly all Orthodox Churches remain WCC members today.