[A]fter Zhiyi’s time, through the efforts especially of Zhanran and the Korean scholar-monk Chegwan, the Tiantai school gradually developed a model that divides the Buddha’s teaching career into five periods that span fifty years. According to this model, the Buddha began by preaching the Flower Garland Sūtra (Avatamsaka Sūtra), a highly advanced doctrine directed solely to bodhisattvas. None of the śrāvakas in the assembly could understand it and were struck dumb, just as the impoverished son was terrified when first forcibly approached by his father’s attendants. Seeing that the Flower Garland teaching was beyond his auditors’ capacity, the Buddha then backtracked and for twenty years preached the āgamas, … emphasizing the four noble truths, the twelve-linked chain of dependent origination, and the goal of nirvāṇa — that is, the teachings sometimes disparaged as the “Hinayāna.” This period corresponds to the wealthy man hiring his son to sweep manure for twenty years. In the third period, seeing that his followers were maturing, the Buddha preached the vaipulya or introductory Mahāyāna teachings such as the Vimalakirti Sūtra, which criticize the one-sided emphasis on emptiness and detachment found in the āgamas and instead extol the way of the bodhisattva. This corresponds to the son having “free access to his father’s house” yet still living in his own humble quarters. In the fourth period, the Buddha preached the prajn͂ā or wisdom teachings, which integrate all of his teachings up to that point in the two discernments of emptiness and wisdom by which bodhisattvas both uproot attachment and act compassionately in the world. This corresponds to the wealthy man entrusting the care of his fortune to his impoverished son. Then finally, in the fifth period, during the last eight years of his life, the Buddha set aside the coarse and incomplete provisional teachings of the preceding four periods and preached the perfect teaching that opens buddhahood to all. This teaching is represented by the Lotus Sūtra, and — in the Tiantai reading — restated in the Nirvāṇa Sūtra, said to have been preached just before the Buddha’s passing. This corresponds to the father, now approaching death, publicly acknowledging his son and bequeathing all of his wealth to him. In this way, the parable of the wealthy householder provided a basis for grasping the entirety of the Buddha’s teachings as integrated into a single, comprehensive chronological and soteriological agenda, by which he sought to gradually cultivate his followers’ capacity until they were mature enough to receive and accept the message of the one buddha vehicle.