The Tiantai school divided the Buddha’s fifty years of teaching into five periods of varying degrees of profundity. The first period occurred during the first few weeks that Śākyamuni Buddha sat beneath the Bodhi Tree. During that time, he taught the Flower Garland Sūtra, although Nichiren points out later in Kaimoku-shō that it would be more accurate to say that it was the bodhisattvas who were present that actually did the teaching. Starting with the discourse on the Four Noble Truths taught at the Deer Park to the five ascetics, Śākyamuni Buddha spent twelve years teaching the pre-Mahāyāna (aka Hinayāna) teachings found in the Āgama sūtras. After that he spent eight years teaching the preliminary Mahāyāna teachings of the Vaipulya or Expanded sūtras. He taught the Perfection of Wisdom sūtras during the twenty-two years that followed that. For the last eight years of his life, the Buddha taught the Lotus Sūtra. On the very last day and night of his life the Buddha taught the Mahāyāna Mahāparinirvāṇa Sūtra. It should be noted that even Nichiren points out in other writings that these time spans are uncertain. In any case, modern textual scholarship would dismiss all of this as arbitrary, especially since the Mahāyāna sūtras are now seen as compositions arising after the Buddha’s lifetime. Nevertheless, Mahāyāna Buddhism accepts these sūtras as embodying the word of the Buddha in the sense that they convey the full depths of the Buddha’s insight and compassion. The Tiantai system of classifying the sūtras into five periods of teaching can still be seen as a useful way of approaching the sūtras in terms of how they build upon one another and lead those who put them into practice into deeper and subtler insights.