This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
At the Uniting General Council held in Nairobi, Kenya, from 20 to 30 August 1970, two international bodies became one. The Alliance of Reformed Churches Throughout the World Holding the Presbyterian System merged with the International Congregational Council to form the World Alliance of Reformed Churches.
The new body brought together more than two hundred Presbyterian, Reformed, Congregational and United member churches spread across more than a hundred countries. Two separate international structures, one built around Presbyterian church government and one around Congregational polity, had until Nairobi represented related but organizationally distinct wings of the Reformed family, each with its own council, its own membership rolls and its own history of ecumenical work.
The Nairobi union did not mark the end of the story. In June 2010, the World Alliance of Reformed Churches itself merged again, this time with the Reformed Ecumenical Council, forming the World Communion of Reformed Churches, a later body carrying a different name from the one founded at Nairobi, though the two are sometimes confused for each other.
What the 1970 Nairobi council changed for the Reformed tradition's spread was uniting two separate international structures, one Presbyterian and one Congregational, into a single global body speaking for more than two hundred churches in over a hundred countries, a union that itself became one more building block toward the still broader World Communion of Reformed Churches formed forty years later.