The provision for retaining prisoners to care for parents in ancient penal systems allowed criminals sentenced to death, exile, or penal servitude to temporarily postpone the execution of their punishments if their parents or grandparents were elderly and had no other adult descendants to care for them. This enabled them to tend to their elders until their passing. Originating in the Northern Wei Dynasty, the system was refined during the Tang Dynasty and persisted through the Ming and Qing Dynasties, reflecting the balance between legal principles and human sentiment in ancient law. The "Wei Shu · Xing Fa Zhi" (Book of Wei · Treatise on Penal Laws) records that death-row prisoners with grandparents or parents aged seventy or above and without other caregivers could petition the emperor; those sentenced to exile would first receive flogging before returning home to "retain and care for their parents," with the punishment carried out only after the elders' death. During this care period, general amnesties typically did not apply to those sentenced to exile.