It is narrated from Sayyiduna Ali (may Allah be pleased with him) that once Chosroes sent a gift to the Prophet (peace and blessings be upon him), and he (peace be upon him) accepted it. Similarly, Caesar sent a gift and he (peace and blessings be upon him) accepted it as well, and when other kings sent gifts, he (peace and blessings be upon him) accepted those too.
Hadith Referenceمسند احمد / مسند الخلفاء الراشدين / 1235
Hadith Gradingحکم دارالسلام:اسناده ضعيف لضعف ثوير بن أبي فاختة، وأخذ الهدية من المشركين لقصد تأنيسهم وتأليفهم على الاسلام ثابت عنه