The Half-Life of a Founding Sin: Legitimacy Inheritance and the Multi-Generational Management of Dynastic Usurpation

The study of dynastic legitimacy in premodern China and comparable polities has concentrated overwhelmingly on two moments: the founding generation's active construction of legitimating claims, and the retrospective, politically disinterested historiographical debate of centuries later. This paper argues that a third, intermediate condition has received comparatively little systematic attention: the multi-generational interval during which a dynasty is neither actively founding its legitimacy nor safely distant from the question, but remains politically — not merely academically — entangled with a founder's compromised or violent path to power. The paper terms this condition legitimacy inheritance and proposes that it be studied as a measurable process with a describable decay curve, analogous to a half-life, rather than as a binary state of stain or resolution. The paper develops this argument through three Chinese case studies selected specifically because each documents a different strategy for managing an inherited founding sin, and because each permits the strategy to be dated with reasonable precision against the documentary record. Eastern Jin's relationship to Sima Yi's 249 coup against Cao Shuang is examined through the historian Xi Zuochi (c. 317–384), whose Han Jin Chunqiu is conventionally read as abstract legitimacy theory reclassifying Shu Han rather than Cao Wei as the true Han successor. This paper argues, from the documented chronology of Xi Zuochi's career under the regent Huan Wen, that the work is better read as contemporary political intervention: composed during the years Huan Wen was visibly retracing Cao Cao's own path toward dynastic transfer, including Huan Wen's 371 deposition of an emperor and his demand for the Nine Bestowments — the identical ceremonial honors Cao Cao had claimed in 213, seven years before Cao Pi completed the transfer those honors were understood to prepare; Huan Wen, unlike Cao Cao, died before his own son could complete the equivalent transfer. The Ming dynasty's relationship to the Yongle Emperor's 1402 usurpation of his nephew, the Jianwen Emperor, is examined through a documented three-stage rehabilitation timeline: erasure in 1402, partial restoration of the reign title under the Wanli Emperor in 1595 (193 years later, within the same dynasty), and full posthumous restoration of imperial status only in 1736, under the Qianlong Emperor of the conquering Qing dynasty (334 years later, under a successor polity with no institutional stake in the outcome). The Song dynasty's relationship to Taizong's succession of his brother Taizu in 976, under circumstances ("the shadow of the candle, the sound of the axe") that later Song sources themselves record as suspicious, is examined as a third strategy distinct from both: neither open dissident theory published within the dynasty (as at Eastern Jin) nor a formal erasure later formally reversed (as at Ming), but the manufacture of a legitimating legend, the Golden Casket Covenant, that foreclosed the need for either. The paper argues these three strategies — competing theory, erasure-and-restoration, and legend-substitution — are not idiosyncratic to their cases but describe a general typology available to any dynasty managing an inherited legitimacy deficit, and tests this typology briefly against Byzantine post-usurpation dynasties, Constantine's Rome, and the Carolingian deposition of the Merovingians. The paper further argues that the two comparative cases most often placed alongside these in existing discussion — the Ming dynasty's relationship to the preceding Yuan, and the Qing dynasty's relationship to the preceding Ming — belong to a structurally distinct category, conquest-dynasty legitimation, which poses the different question of whether an ethnically or dynastically external polity may hold Heaven's Mandate at all, rather than the question this paper examines, which is how a dynast