The Seal and the Envoys
The truce of Ḥudaybiyyah gave the Prophet ﷺ something he had not had in nineteen years of his mission: a settled frontier and time. He used it to write outward. Told that foreign rulers would not read a letter without a seal, he had a silver ring made engraved in three lines — Muḥammad / rasūl / Allāh — and sent envoys carrying letters to the sovereigns of the known world.1
The letter to Heraclius survives in full in Ṣaḥīḥ al-Bukhārī, embedded in one of the most remarkable narrations in the collection: Abū Sufyān ibn Ḥarb — at that time still the leader of the Makkan opposition — happened to be in Syria on trade when the letter arrived, was summoned before the emperor, and was cross-examined about the man who had sent it.2
To Heraclius, Emperor of Rome
In the name of God, the Entirely Merciful, the Especially Merciful.
From Muḥammad, the servant of God and His Messenger, to Heraclius, the great one of the Romans.
Peace be upon whoever follows the guidance.
To proceed: I call you with the call of Islam. Accept Islam and you will be safe; accept Islam and God will give you your reward twice over. But if you turn away, then upon you is the sin of your subjects.
“O People of the Scripture, come to a word that is equitable between us and you — that we will not worship except God, and not associate anything with Him, and not take one another as lords instead of God.” And if they turn away, then say, “Bear witness that we are Muslims [submitting to Him].”
The Cross-Examination of Abū Sufyān
Heraclius put a series of questions to Abū Sufyān, and the exchange is preserved verbatim. He asked about the man's lineage — noble, Abū Sufyān said. Whether anyone before him had made such a claim — no. Whether there was a king among his forefathers — no. Whether the noble or the weak followed him — the weak. Whether his followers increased or decreased — increased. Whether any turned back from the religion out of dissatisfaction — no. Whether he had ever been known to lie before he said what he said — no. Whether he betrayed agreements — no.2
Abū Sufyān, narrating it afterward, admitted that the only thing he was able to insert against him was the remark that they were currently in a truce and he did not know what he would do with it. Heraclius then explained what each answer had meant to him — that prophets are sent among the noblest of their people, that the weak are the followers of messengers, that a faith is true when none abandons it out of resentment, and that a man who does not lie about people does not lie about God — and concluded: “If what you say is true, he will assuredly take the ground beneath my two feet.”2
Al-Bukhārī notes that the letter was read, that a clamour of voices was raised, and that Abū Sufyān and his party were expelled from the court. Whatever Heraclius privately concluded, he did not convert; and Abū Sufyān said afterward that from that day the matter of Ibn Abī Kabshah — his contemptuous name for the Prophet ﷺ — could not be got out of his mind, and that he became certain the man would prevail.2
To the Negus, and to Chosroes
To the Negus of Abyssinia — who had already sheltered the Muslim emigrants years earlier and refused to surrender them — the letter was framed for a Christian king who had already shown his hand: “Peace be upon whoever follows the guidance… I bear witness that ʿĪsā son of Maryam is the spirit of God and His word, which He cast to Maryam the virgin, the good, the pure.”3
To Chosroes II of Persia the letter was sent in the same form. The classical sources relate that he tore it to pieces, and that when the Prophet ﷺ was told, he said, “May God tear his kingdom to pieces.” Chosroes was murdered by his own son within a few years, and the Sasanian empire — which had defeated Byzantium and taken Jerusalem within living memory — did not survive the generation.4
The letters mark a turn in the sīrah that is easy to pass over. In 622 the Prophet ﷺ had entered Madīnah as a refugee from a town of a few thousand people. Six years later he was writing, over his own seal, to the two superpowers that had divided the civilised world between them, addressing each in the same voice and on the same terms.15