This chapter begins after the Civil War’s guns fell silent, leaving the short-lived Confederacy dead on the battlefield. As this book concerns the long career of the Lost Cause, examining the mythology itself is critical. I present a composite definition of the amorphous Lost Cause, arguing for what I consider to be its three core features—victimhood, theodicy, and ethnonationalism. From the chaotic years following Appomattox through to the high-water mark of the influence of hereditary commemorative organizations such as the United Daughters of the Confederacy, I track how the myth of the Lost Cause grew out of the immediate aftermath of defeat. From its origins as something of an anesthetic to ameliorate the pain of a lost war and a devastated South, the myth grew into a multi-generational pseudo-historical phenomenon. It spread well beyond the boundaries of the former Confederacy, lending itself to religious metaphor and eventually finding mainstream relevance as monuments to it were built across the country.