Nichiren was a Japanese Buddhist monk who lived during the 13th century. He is best known for founding the Nichiren Buddhism school, which emphasizes the chanting of the Lotus Sutra as a means to attain enlightenment. Nichiren believed that this sutra contained the ultimate truth of Buddhism and that it could lead to personal and societal transformation. Nichiren's teachings focused on the importance of faith, practice, and the realization of one's inherent Buddha nature. He faced significant opposition during his lifetime, leading to his exile, but his followers continued to spread his teachings, which have influenced various sects of Buddhism in Japan and around the world.