The Chinese Tiantai patriarch Zhiyi, working in the late sixth century, faced a problem earlier interpreters had mostly stepped around: the Buddhist scriptures reaching China from India did not agree with each other, teaching rebirth cycles one place and their transcendence another, self denial in one text and the fullness of buddha nature in the next, all attributed to the same single teacher. Zhiyi's classification resolved the contradiction by reading it as pedagogy rather than as error, dividing the Buddha's teaching career into five periods and describing the content and method of each period using eight teachings, four naming what was taught and four naming how it was delivered to audiences of differing capacity. On this reading, apparently incompatible sutras are not competing claims about the same audience at the same moment, they are different lessons pitched at where their hearers actually stood, each one true for its stage and each one superseded, not contradicted, by what came after. The Lotus Sutra sits at the summit of the sequence in Zhiyi's system because Tiantai reads it as the point where the Buddha sets the earlier accommodations aside and states plainly that they were accommodations, unifying every vehicle that came before into the single one the whole scheme had been building toward.