Caesar, inviting him to embrace Islam. He dispatched the letter with Ḍiḥyah al-Kalbī, and the Messenger of Allah ﷺ instructed him to hand it to the governor of Busra, who would then deliver it to Caesar. The governor duly forwarded it.

At that time, after Allah had lifted the Persian armies from his realm, Caesar had walked barefoot from Ḥimṣ to Aelia (Jerusalem) in gratitude for the favor Allah had granted him. When the letter of the Messenger of Allah ﷺ reached him and he had read it, he said, “Find me someone here from his people so that we may question them.”

Ibn ʿAbbās said: Abū Sufyān told me that he was in Syria with several men of Quraysh who had come for trade during the truce between the Messenger of Allah ﷺ and the unbelievers of Quraysh.

Abū Sufyān continued: “Caesar’s envoy found us somewhere in Syria and brought us to Aelia. We were admitted before him, and there he sat on his throne wearing a crown, surrounded by the dignitaries of Rome. He said to his interpreter, ‘Ask them which of them is most closely related to the man who claims to be a prophet.’ I said, ‘I am the nearest to him in lineage.’ He asked, ‘What is the exact relationship between you and him?’ I replied, ‘He is my cousin.’ There was no one from Banū ʿAbd Manāf in the caravan that day except me. He said, ‘Bring him closer to me,’ then ordered my companions to stand behind me, by my shoulder, and said to his interpreter, ‘Tell his companions that I intend to question this man about the one who claims to be a prophet; if he lies, let them expose his lie.’

Abū Sufyān said: ‘By Allah, had I not been ashamed that my companions might report a falsehood from me, I would surely have lied about him.’ He then said to his interpreter, ‘Ask him: How is this man regarded among you in terms of lineage?’ I replied, ‘He is of noble lineage among us.’ He asked, ‘Has anyone among you ever made this claim before him?’ I answered, ‘No.’ He asked, ‘Did you ever accuse him of lying before he said what he now says?’ I said, ‘No.’ He asked, ‘Is there any king among his forefathers?’ I said, ‘No.’ He asked, ‘Do the nobles or the weak follow him?’ I replied, ‘Rather, the weak follow him.’ He asked, ‘Are they increasing or decreasing?’ I answered, ‘They are increasing.’ He asked, ‘Does anyone ever renounce the religion out of displeasure after entering it?’