Mahomet now began to place himself on a level with crowned heads. In 628 he had a seal made with the inscription upon it: "Mahomet the messenger of God." Furnished with this official seal, he despatched six messengers with letters to the Emperor Heraclius; to the King of Abyssinia; to the Shah of Persia; to Mokawkas, lord of Alexandria; to Harith the Ghassanite chief; and to Hawda in Yamama, a province of Arabia. The purport of all these missives was an exhortation to the various sovereigns and chiefs to embrace the new religion, and a promise that God would reward them if they did, with a warning that they would bear the guilt of their subjects if they did not. In the same year Mahomet besieged the town of Chaybar, whose inhabitants were Jews. Many of them were killed; the rest were permitted to withdraw with their families. Kinana, their chief, was executed; and his wife Cafyya was added to the already numerous harem of the victor. The following year, 629, witnessed the performance by the Moslems of the pilgrimage to Mecca for the first time since the Hegira. The prophet summoned those who had accompanied him to Hodaybiya the year before to go with him now. The Koreish, according to the stipulations of the treaty, left the city; the Moslems entered it, performed their devotions, and retired after three days. This year was also marked by a signal victory over a Ghassanite chief, who had executed a Mussulman envoy. In January, 630, taking advantage of the invitation of an allied tribe who had quarreled with Mecca, Mahomet quitted Medina with a large army for the purpose of taking that city. The exploit was facilitated by the desertion of the general of the Koreish, Abu Sofyân, who privately escaped to the Moslem camp and made his confession of faith. Next day the forces of the prophet entered Mecca with scarcely any resistance. In the following year he laid down the terms upon which the conquered city was to be dealt with. Abu Bakr, accompanied by 300 Moslems, was sent to Mecca as leader of the pilgrims. Ali was charged to make the proclamation to the people which is found in the 9th Sura of the Koran.