Sayyiduna Abu Humayd Sa'idi (may Allah be pleased with him) said: The ruler of Aylah sent a letter to the Messenger of Allah (peace and blessings be upon him) and sent a gift of a white mule. The Messenger of Allah (peace and blessings be upon him) also wrote him a letter in reply and sent a cloak as a gift.
Hadith Takhrijاس روایت کی سند صحیح اور حدیث متفق علیہ ہے۔ دیکھئے: [بخاري 1481] ، [مسلم 1392] ، [أحمد 424/5] ، [أبوداؤد 3079، وغيرهم]
Brief Explanation
(Commentary on Ahadith 2529 to 2531)
The sending of gifts by Shah Dhi Yazan and the ruler of Aylah, Yuhanna bin Rubah, to the Prophet sallallahu alayhi wa sallam, and the acceptance of these gifts by the Prophet sallallahu alayhi wa sallam, is established from these ahadith.
Therefore, the head of state may accept gifts from polytheist rulers.