In one day only...

In one day only, he wrote six letters to al-Najashi, the king of Abyssinia, Caesar of Rome; Khosrow Parviz of Iran, al-Muqawqas of Egypt, Harith ibn Abi-Shimr al-Ghassani of Damascus, and Hawdhah Ibn `Ali of Yamamah, as well as many other kings and governors.[^2] These letters were written in Dhu’l-Hijjah of the sixth year of Hegira or Muharram of the seventh. Of course, this was just the beginning of the universal invitation to Islam.

Moreover, from that day on and up to his last day of life, the Holy Prophet continued writing letters to the different countries of the world.[^3] The content of all these letters was identical and all of them were written in a simple, explicit and decisive style. However, reactions of the world leaders were not identical. Conquest of Khaybar Khaybar consisted of several castles. Its people were engaged in agriculture and animal husbandry.

Due to its good agricultural capacities, it was referred to as the wheat store of Hijaz.[^4] Its people also enjoyed good economic prosperity. The great goods and ammunitions which fell in the hands of Muslims after the collapse of the castles witness to this issue.

The very structure of the castles was strong and enduring and the number of their troops was in thousands.[^5] For this reason, they considered themselves strong enough to stop the attacks of Muslims.[^6] The Jews of Khaybar made use of any chance available to try to destroy the newly built Islamic government as their city was turned into a permanent center for conspiracies against Islam.

Having been defeated in Medina, the chiefs of Banu’l-Nazir joined Khaybar to cooperate with them against Islam. In the sixth year of Hegira, Sallam ibn Abi’l-Huqayq, one of Banu’l-Nazir's chiefs who had obtained the leadership of the Jews of Khaybar through cooperation with the tribe of Ghatafan and other infidel tribes, gathered a great troop to fight against Muslims.

After he was killed by Muslims due to plotting conspiracies against them, people of Khaybar appointed Usayr ibn Zarim as their leader.[^7] This man, too, engaged himself in aggression and provocation of tribes against Muslims.[^8] To eradicate the previous signs of enmity, the Holy Prophet dispatched a group under the supervision of `Abdullah ibn Rawahah to the newly appointed leader to secure his consent for peace.

The new leader, together with `Abdullah and a group of Jews, was on his way to Medina to talk to the Holy Prophet.