Another important source of information about Egypt during the reign of Djedkare Isesi is the Abusir papyri . These are administrative documents , covering a period of 24 years during Djedkare 's reign ; they was discovered in the mortuary temples of pharaohs Neferirkare Kakai , Neferefre and queen Khentkaus II . In addition to these texts , the earliest letters on papyrus preserved to the present day also date to Djedkare 's reign , dealing with administrative or private matters .