This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
From 18 to 28 June 2010, delegates meeting at Calvin College in Grand Rapids, Michigan, completed the merger of the World Alliance of Reformed Churches, itself formed at Nairobi in 1970, with the smaller and more theologically conservative Reformed Ecumenical Council, founded in 1946. The union created the World Communion of Reformed Churches.
The scale of the new body was considerable. It brought together more than 80 million Reformed Christians in 108 countries, joining 214 World Alliance member churches from 107 countries with 41 Reformed Ecumenical Council member churches from 25 countries.
The two sides approved the union differently. The World Alliance's own process involved debate over women's representation that amended the new body's constitution to require that any delegation of four or more members be at least half women, while the Reformed Ecumenical Council approved the union unanimously and without debate.
What the 2010 Grand Rapids council changed for the Reformed tradition's spread was completing a consolidation forty years in the making, folding a second, more conservative international body into the union first formed at Nairobi and setting a gender representation rule for the combined body's delegations along the way.