See studies by V. Peters (1965), J. W. Bennett (1967), and J. A. Hostelter (1975).
After enduring persecution for a time (see Anabaptist), the Brethren migrated to North America in three separate groups from 1719 to 1733. There they established themselves at Germantown, Philadelphia, Pennsylvania, and from there moved south and west along with other pioneers.
The Brethren Church shares its early unstable heritage with the Church of the Brethren but was separated in 1883, being the most progressive of the three groups resulting from this split at the time of H. R. Holsinger. The most conservative of the groups (the Old Order, centered in Dayton, OH) is now known as the German Baptist church. The current Church of the Brethren was the middle (or conservative) group. This split was not really about doctrine (at the time, though the groups have drifted apart since) but over such things as the starting of Sunday Schools, the holding of revival meetings, and the use of an indoor baptistry rather than running water in a creek or river. The progressive group (Brethren Church) includes a denomination with headquarters in Ashland, Ohio. In 1939 the Progressives split into two denominations, with those seeking an open position to the issue of eternal security maintaining the name Brethren Church, and those seeking a firm affirmation of eternal security becoming the Fellowship of Grace Brethren Churches (FGBC), commonly called the Grace Brethren Church, headquartered in Winona Lake, Indiana. The Grace Brethren experienced a split in the 1990s (primarily related to the connection between water baptism and church membership), with a minority of churches forming the Conservative Grace Brethren Churches, International (CGBCI). In 2007, families from both the FGBC and CGBCI formed a new fellowship calling themselves the Brethren Reformed Church.