This chapter presents an alternative to the standard narrative of the decline of the mission enterprise, which tends to focus exclusively on Spanish politics.The chapter argues that a series of catastrophic demographic crises ultimately marked the definitive end of mendicant expansion.At least forty percent of the indigenous population perished between 1575 and 1595.In many areas, the population fell below the critical levels necessary for the mission enterprise to remain economically and socially sustainable.The civil records of the viceroyalty show the results: stalling construction projects, diminishing tributes, and declining workforces. Communities had once committed to raising doctrina monasteries now reported widespread starvation and lamented that their workforces could no longer sustain the Church.Thus, while earlier crises wrought by conquests and epidemics had seen vigorous recovery efforts that stimulated the construction and expansion of the mission enterprise, late-sixteenth century demographic crises rendered the mission unsustainable for a rising number of communities.This late-century crisis opened a new phase in the history of the mission enterprise, in which mendicants curtailed once-ambitious construction campaigns, downsized the scale and extent of their operations, and halted the expansion of the enterprise.Friars and native rulers turned to defending the infrastructure that earlier generations had built, and many of these jurisdictions came to serve as centers for concentrating outlying populations in the congregaciones of the early seventeenth century.