I need information on the letters written by the holy Prophet to different rulers to embrace Islam.

All perfect praise be to Allaah, The Lord of the Worlds.  I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

Ibn Sa'd reported in his book Tabaqaat from Anas that the Prophet in the sixth year after Hijrah, in the month of Thul-Hijjah sent delegates with letters to various kings calling them to Islam. When the Prophet was told that kings do not read unsealed letters, he sealed the letters with a silver seal engraved with the words: "Muhammad, the Messenger of Allaah". He sent six delegates in one day in the seventh year A.H., in the month of Muharram. The persons he appointed as delegates to the kings were masters of their language. Imam Muslim narrated from Anas he said, "The Prophet of Allaah wrote to Chosroes (King of Persia), Caesar (Emperor of Rome), Negus (King of Abyssinia) and every (other) despot inviting them to Allaah, the Exalted. And this Negus was not the one for whom the Messenger of Allaah had said the funeral prayers".

For more details about these letters and their content please read the E-Books of Seerah (Prophetic biography) on our site.

Allaah Knows best.