The 3,500-year-old Rhind Papyrus hides a war report on its back
Rhind Mathematical Papyrus
The Rhind Mathematical Papyrus, copied around 1550 BC by the scribe Ahmes, is the largest and most famous surviving example of ancient Egyptian mathematics, packed with fraction tables, algebra, geometry, and a value for pi accurate to within one percent. Yet its verso carries a stray historical note: on day 23 of the first month of Akhet, "he of the South" broke into Tjaru, which scholars read as the Theban king Ahmose I closing in on the Hyksos.
This book was copied in regnal year 33, month 4 of Akhet, under the majesty of the King of Upper and Lower Egypt, Awserre, given life, from an ancient copy made in the time of the King of Upper and Lower Egypt Nimaatre.