Assalamualaikum, I recently heard a sheikh give a speech, he said Prophet (Saw) sent letter to Oman from Amr Ibn al aas, and the two kings: abd and jayfar converted willingly. I have found this to be referenced in Zaad Al maad by Ibn Qayyim. However after this the sheikh said that Amr Ibn al aas also tried to convert their father whose name was "Julanda" and apparently this was the conversation:
"The name of the King of Oman was al-Julanda, and news reached him that Prophet Mohammed (peace and blessing be upon him) had invited him to Islam. Upon hearing this he said, "By Allah who has guided me to the unlettered Prophet, if he commands something good, he is the first to do it, and when he forbids something, he is the first to avoid it. When he conquers he is not proud, and when defeated his is not aggrieved. He fulfils a contract and is true to his promise. I bear witness that he is a prophet", and sheikh said he accepted at hands of nabi (saw)
according to my research I cannot find anything of Julanda , I only find that his sons (abd and jayfar) converted willingly in many different books, How true is that conversation which I listed above, and if anyone could find reference would be appreciated,