Complex sentence: As early as 1988, Joseph W. Tkach Sr. began to make doctrinal changes, at first quietly and slowly at first, but then openly and radically in January 1995.
Split into simpler sentences: As early as 1988, Joseph W. Tkach Sr. began to make doctrinal changes. Doctrinal revisions were made quietly and slowly at first, but then openly and radically in January 1995.