A 360-Day Administrative Year in Ancient Israel: Judahite Portable Calendars and the Flood Account

Administrators in ancient Judah used schematic 30-day months and a 360-day year alongside other annual frameworks. This year was never practiced as a “calendar” for any cultic or administrative purpose, but rather served as a convenient framework for long-term planning, as well as for literary accounts that were not anchored to a concrete calendar year. Examples for such a usage are attested here from Mesopotamian texts. Material evidence for the 360-day year in Judah comes forth from a series of small perforated bone plaques from various sites in Iron Age Judah. One such item was recently unearthed in the city of David. These objects can reasonably be understood as reflecting a schematic 360-day year, serving as desk calendars for Judahite administrators. Several priestly pentateuchal texts are best understood against this background, such as the dating of some festivals and most notably the dates in the Flood narrative (Gen 7–8). The original dating system is best represented in LXX Gen 7:11, while the reading of MT is a late modification, inserted later, when calendar debates took a central place in the religious discourse. MT is thus a link in a chain of later reworking of this narrative in Second Temple literature. The 360-day year is thus a unique case where material culture dovetails with literary evidence, and may shed light on the material culture of priestly sources. This insight is significant for future studies of biblical time reckoning.