Wesley's Authority

In Chapter 1 of American Methodism, Wesley is characterized quite frequently as demanding loyalty, discipline, and order. The way in which he organizes the Methodist society seems to be quite authoritative, with himself as the leader who has the final say about nearly everything. Rankin "demands acceptance of Wesley's authority," and Wesley instructs preachers to preach no doctrine other than what is found in his New Testament notes and his sermon volumes. I can see the beginnings of some of this desire for total authority in earlier writings of Wesley's, but I'm curious as to how and why this practice was developed to the state described in this chapter.