As early as the 16th century, natural Philosophers like Bruno, Dee, and Francis Bacon were attempting to rehabilitate Bacon's reputation and to portray him as a scientific pioneer who had avoided the petty bickering of his contemporaries to attempt a rational understanding of nature. By the 19th century, commenters following Whewell considered that "Bacon... was not appreciated in his age because he was so completely in advance of it; he is a 16th or 17th century Philosopher, whose lot has been by some accident cast in the 13th century". His assertions in the Opus Majus that "theories supplied by reason should be verified by sensory data, aided by instruments, and corroborated by trustworthy witnesses" were (and still are) considered "one of the first important formulations of the scientific method on record".