 According to R. C. Bell, the earliest known board for the game includes diagonal lines and was "cut into the roofing slabs of the temple at Kurna in Egypt"; he estimated a date for them of  BCE.However, Friedrich Berger wrote that some of the diagrams at Kurna include Coptic crosses, making it "doubtful" that the diagrams date to 1400 BCE.Berger concluded, "certainly they cannot be dated."