The TRUE Identity of the Church of GOD throughout history is, in the eyes of many, greatly facilitated by the Seven Churches addressed in Revelation 2 and 3. One particular Identification seems more Enigmatic than any other.
Though the idea of the seven churches of Asia Minor in Revelation 2 & 3 enjoy widespread regard as being typical of the Church throughout history, among certain fundamentalists they're seen even as representing seven successive Church Eras by which we can identify and track certain unique characteristics or attitudes of God's people down thru time. I can recall as a young person in a Conservative Baptist church being led thru church history using these seven as a framework. Though the minister then presented main stream religious benchmarks as being fulfillments, yet the general idea is present with them as it is in the Churches of God, that it's an outline of the various phases thru which the True Church passed over the ages since the 'Ephesian' Church of the first century.
But within Church of God groups, there are also significant numbers which hold the teaching of Church Eras with certain skepticism and even pointed disregard.