It has been narrated on the authority of Anas that the Prophet (ﷺ) of Allah (ﷺ) wrote to Chosroes (King of Persia), Caesar (Emperor of Rome), Negus (King of Abyssinia) and every (other) despot inviting them to Allah, the Exalted. And this Negus was not the one for whom the Messenger of Allah (ﷺ) had said the funeral prayers.
Hadith Referenceصحيح مسلم / كتاب الجهاد والسير / 1774
The tradition has been narrated on the authority of Anas bin Malik (RA) (the same narrator) through a different chain of transmitters, but this version does not mention: "And he was not the Negus for whom the Prophet (ﷺ) had said the funeral prayers."
Hadith Referenceصحيح مسلم / كتاب الجهاد والسير / 1774