Here is an article called the Origin of Denominations at http://home.att.net/~jackthompson/page173.htm
I haven't had a chance to read the entire study, but if you read just Lessons 3, 4, 5, & 6, you will see how the falling away began and how things crept into the church and into church doctrine that weren't based on scripture.  As you know Jesus told us that the wise man built his house on the rock and the foolish man's house had no foundation.  Jesus Christ, the Word, is the rock of our salvation, and church doctrine should be based on scripture which is the word of God.  Faith should not be placed in a doctrine that doesn't have a Bible scripture to base it on otherwise it is an empty promise which promises nothing, and is lacking the foundation of the word of God.