Quote

The breach of al-Mamun

Legends of treasures hidden within Khufu's pyramid persisted. They found their way into the tale of The Thousand and One Nights, along with a story that Caliph al-Mamun, son of Haroun al-Rashid, was the first to break into it, around AD 820. With great effort, he forced a passage with iron picks and crowbars, and by pouring cold vinegar on to fire-heated stones. There is indeed a breach - now the tourist entrance - below and to one side of the original entrance. But just when the pyramid was violated remains a puzzle, though it is possible that it was in ancient times. It seems that whoever carried out the operation aimed straight for a point opposite the juncture of the descending and ascending passages before turning east to break through beyond the granite plugs. Saite Period (26th dynasty) priests perhaps made repairs, since at this time there was an attempt to restore Old Kingdom monuments. If the passage was forced in pharaonic times, however, it must have been gaping open in AD 820 - and presumably any repairs would have been detectable. Mamun's men may have enlarged the passage made by ancient robbers.

These confusions do not inspire confidence in the historicity of the story of al-Mamun. Accounts of wild events and fabulous discoveries inside the pyramid increase our doubts. A more sober, and perhaps more trustworthy, version is that of Abu Szalt of Spain. He tells of Mamun's men uncovering an ascending passage. At its end was a quadrangular chamber containing a sarcophagus. 'The lid was forced open, but nothing was discovered excepting some bones completely decayed by time. But doubt is cast again by Denys of Telmahre, the Jacobite Patriarch of Antioch. He accompanied Mamun's party and states that the Great Pyramid was already opened at the time of their visit.

Lehner. The Complete Pyramids, p. 41.