ßÊÇÈ ÇáÃÍßÇã : Hadeeth No:6703 : Anas bin Malik:
When the Prophet intended to write to the Byzantines, the people said,
"They do not read a letter unless it is sealed (stamped)." Therefore
the Prophet took a silver ring----as if I am looking at its glitter
now----and its engraving was: 'Muhammad, Apostle of Allah'...