the ruler of Castile, and the people of al-Andalus boast of possessing it; this is something well-known and widely acknowledged.

Sunaid—al-Bukhārī’s teacher in his Qurʾānic commentary—narrated in that work:

Hishām related to us, saying: Ḥuṣayn informed us on the authority of ʿAbdallāh ibn Shaddād ibn al-Hād, who said:
“When the Messenger of Allah, peace and blessings be upon him, wrote to Heraclius and he read the letter, he gathered the Romans together, but they refused to accept it. Then, when Sunday came, their bishop did not attend…”