History is not a snap-shot. Events happen, and the true record of them follows at a distance. Sometimes the early report is too voluminous, and it takes time to reduce it to truth by a winnowing process that divides chaff from grain. This has been the case regarding every great modern battle. Sometimes, on the other hand, the event was obscure and became important through the rise of other, later conditions; in which case, instead of winnowing, the historian sets himself to gleaning the field and making his grist out of scattered bits of its fruitage. This has been the case regarding the Chicago massacre of 1812.