History of Japan men instead joined forces with Emperor Go-Daigo and overthrew the Kamakura shogunate. Japan nevertheless entered a period of prosperity and population growth starting around 1250. In rural areas, the greater use of iron tools and fertilizer, improved irrigation techniques, and double-cropping increased productivity and rural villages grew. Fewer famines and epidemics allowed cities to grow and commerce to boom. Buddhism, which had been largely a religion of the elites, was brought to the masses by prominent monks, such as Hōnen (1133–1212), who established Pure Land Buddhism in Japan, and Nichiren (1222–82), who founded Nichiren Buddhism. Zen Buddhism spread widely among
Faith in Buddhism bird-like deities and violent spirits which previously were the focus of pre-Buddhist cults became guardians of the Buddhist teaching. This process of adopting deities as part of Buddhism often occurred when Buddhist devotees or monks did not fully renounce their former devotions when embracing Buddhism. In the early Pāli scriptures, as well as in some customs in traditional Buddhist societies, traces can still be found of the period that Buddhism competed with "nāga" worship and assimilated some of its features. In some Buddhist countries like Japan, a perspective arose of the human world as a microcosm of the macrocosmic realms