—the rout of the Persians, the conquest of Egypt, and other campaigns that took place in the time of ʿUmar ibn al-Khattab—matters they affirm with certainty, even though outsiders know nothing about them.

In the same way, the chronicles of later kings and the great events of history are familiar to those who study them. Indeed, the experts in biographical criticism possess precise information about the individual conditions of the Companions, the Successors, and those who followed them—men such as ʿAbd Allah ibn ʿUmar, Ibn ʿAbbas, Abu Saʿid, Abu Hurayrah, ʿAbd Allah ibn Masʿud, Anas ibn Malik, Ubayy ibn Kaʿb, Muʿadh ibn Jabal, Saʿid ibn al-Musayyib, al-Hasan al-Basri, ʿAlqamah, al-Aswad, and many others—details that no one outside their field is aware of.

So too the scholars of grammar know the circumstances of Sībawayh, al-Akhfash, al-Mubarrad, al-Zajjāj, and al-Farrāʾ.