The law has a long memory – forget elephants, it looks far beyond any ordinary mortal span. Technically speaking, its memory kicks in on 3 September 1189.[i] But even the best memories suffer from deterioration. With such a lengthy span to cover, it is an inevitable commonplace of legal history that facts become lost. Records of rules or events might never be made. Or, if records are made, these might not survive or survive only partially. Those versed in the law also pass on, and might be replaced by others who sing the verses rather differently.
Sometimes, though, knowledge can be lost surprisingly quickly, without any of the standard traumas of intervening centuries. And this sort of loss can occur even in the modern context.