More than seventy-five years ago, Ludwig Keller (1849–1915), German archivist and historian, wrote to the young Mennonite immigrant to the United States, John Horsch (1867–1941), to propose that
just as in the “Evangelical Alliance” Lutherans, Methodists, Baptists, etc., meet from time to time, the Mennonites of the various branches could join with the Quakers, Schwenkfelders, … Dunkers, several branches of the General Baptists, the Hutterian Brethren, several wings of the Presbyterians, etc., in brief all the parties that grew out of old Anabaptism, in an “Old-Evangelical Alliance” [Alt-evangelischen Bunde].