In this brand-new article - the fourth in our Egyptian suite - we explore the papyrus archive from El Lahun using a strictly schematic Egyptian civil calendar and a modern astronomical date for the start of the calendar. This leads to the absolute accession years for three pharaohs of the Egyptian 12th dynasty. The accession years are compatible with recent radiocarbon dates for dynastic Egypt and are confirmed by all twenty-six moon dates with explicit regnal years, as well as by the Sothic date and an additional incomplete moon date included in the archive. Our investigation also sheds light on periods of co-regency, Egyptian practices of Sirius and moon observations, and the reliability of the Turin king list.
