The letters of the prophet Muhammad To the kings beyond Arabia

Late in the six year A.H., on his return from Hudaibiyah,

the Prophet Muhammad decided to send messages to the kings beyond Arabia calling them to Islam.

In order to authenticate the credentials of his envoys,

a silver seal was made in which were graven

the words: “Muhammad the Messenger of Allâh” [Sahih Al-Bukhari 2/872,873]