Carlyle stated that "The history of the world is but the biography of great men", reflecting his belief that heroes shape history through both their personal attributes and divine inspiration.[4][5] In his book On Heroes, Hero-Worship and the Heroic in History, Carlyle set out how he saw history as having turned on the decisions of "heroes", giving detailed analysis of the influence of several such men (including Muhammad, Shakespeare, Luther, Rousseau, Pericles, Napoleon, and Wagner). Carlyle also felt that the study of great men was "profitable" to one's own heroic side; that by examining the lives led by such heroes, one could not help but uncover something about one's true nature.[6]