Nichiren Shōnin (1222-1282), the founder of Nichiren Shū (the Nichiren School) was a Buddhist monk in 13th century Japan. Nichiren Shōnin sought to find the quintessence of the Buddha’s teachings. He was ordained at age 15 and studied widely, travelling across Japan to read Buddhist scriptures and to learn from various teachers.
Having studied all the Buddhist schools in Japan at the time, Nichiren Shōnin came to the conclusion that the Lotus Sūtra was the teaching fully revealing the Buddha's highest teaching, and his true mind, and that by practising the Lotus Sūtra, by chanting the Odaimoku (Namu-myōhō-renge-kyō or Devotion to the Wonderful Dharma of the Lotus Flower Sūtra), all people could attain enlightenment.
Throughout his life, Nichiren Shōnin worked for the happiness of all people, and many of his writings survive to this day. They include letters of encouragement to followers and disciples of his, and also remonstrations with the government at that time. He was a truly great reformer of Buddhism, who brought many people to have faith in the teaching of the Lotus Sūtra.
Age 12 - Entered Seichōji temple
Age 16 - “Left home” and ordained as a monk under the master of Seichōji, Dōzen-bō, and took the name Zeshō-bō Renchō
Age 17 - Went to study Zen and Pure Land Buddhism in Kamakura
Age 19 - Began his studies on Mt. Hiei, near Kyoto
Age 32 - Rikkyō Kaishu: The establishment of Nichiren Shu (the Nichiren School) on
28th April 1253
Age 33 - Went to live at the Matsubagayatsu Hermitage
Age 39 - Wrote the Risshō Ankoku-ron (Treatise on Establishing Peace Throughout the Country by Establishing the True Dharma) and submitted it to Hojo Tokiyori (First remonstration with the government)
Age 40 - Matsubagayatsu Persecution, exiled to Izu Island
Age 42 - Pardoned from exile and returned to Kamakura
Age 43 - Komatsubara Persecution: Ambushed and attacked by Tojo Kagenobu in Awa Province
Age 47 - Presented the Rissho Ankoku-ron to the Shogunate for a second time (Second remonstration)
Age 50 - Tatsunokuchi Persecution: Escaped execution at Tatsunokuchi and was exiled to Sado Island
Age 51 - Wrote Kaimoku-shō (Open Your Eyes)
Age 52 - Wrote Kanjin Honzon-shō (On contemplation of the mind and the focus of devotion)
Age 53 - Was pardoned from exile in Sado, and returned to Kamakura. Met with Taira no Yoritsuna and gave his opinion on the issue of Mongolian invasion (Third remonstration). Entered Mt. Minobu
Age 54 - Wrote Senji-sho (The Selection of the Time)
Age 55 - Wrote Hōon-jō (On Gratitude)
Age 61 - Left Minobu, heading for the hot spring in Hitachi. Arrived at the residence of Ikegami Munenaka.