Fuller is perhaps best known today for his "Nine Principles of War" which have formed the foundation of much of modern military theory since the 1930s, and which were originally derived from a convergence of Fuller's mystical and military interests. The Nine Principles went through several iterations; Fuller stated that "the system evolved from six principles in 1912, rose to eight in 1915, to, virtually, nineteen in 1923, and then descended to nine in 1925". For example, notice how his analysis of General Ulysses S. Grant was presented in 1929.