Anas bin Malik reported,

The Prophet of Allah ﷺ wrote letters to Khosrau, to Caesar, to the Negus, and to every tyrant, calling them to Allah the Exalted. This was not the Negus over whom the Prophet ﷺ performed the funeral prayer.Wazad added in another narration, "And to Ukaydir of Dumah."

Azami 9790

Sahih

عن أنس بن مالك

أن نبي الله ﷺ كتب إلى كسرى، وإلى قيصر، وإلى النجاشي، وإلى كل جبار، يدعوهم إلى الله تعالى، وليس بالنجاشي الذي صلى عليه النبي ﷺ. وزاد في رواية: وأكيدر دومة.

الأعظمي 9790صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Biography of the Prophet ﷺ
Chapter
Prophet ﷺ wrote to kings and rulers inviting them to Islam
Section
Prophet's ﷺ correspondence to leaders and kings
Numbering
Jami al-Kamil 9790 (2nd edition)
Azami 9790