In 1972, some 12,000 Quranic parchment fragments were discovered in the Great Mosque in the Yemeni capital Sana.
A palimpsest is a manuscript page that has been erased so that another text could be written over it.
The Sana Quran palimpsest is significant because the top layer (the text written over what was erased) is the standard Uthmanic version of the Quran.
Beneath this standard Uthmanic version of the Quran (the part that was erased) is a non-Uthmanic version of the Quran. According to Islamic tradition, Uthman compiled the Quran and its several various readings (about twenty years after Muhammad’s death.
Muslims believe Uthman kept one copy for himself in Medina and sent copies to al-Kufa, al-Basra, and Damascus.
He then commanded the destruction of all other Quran fragments and manuscripts.