Sayyiduna Uqbah bin Amir al-Juhani (may Allah be pleased with him) said that Sayyiduna Amr bin al-As and Sayyiduna Shurahbil bin Hasanah (may Allah be pleased with them both) sent Sayyiduna Uqbah (may Allah be pleased with him) to Sayyiduna Abu Bakr al-Siddiq (may Allah be pleased with him) with the head of Yannaq, the patrician of Syria. When the head was brought to Sayyiduna Abu Bakr al-Siddiq (may Allah be pleased with him), he disapproved of it. Sayyiduna Uqbah (may Allah be pleased with him) said: O Khalifah of the Messenger (peace and blessings be upon him), they do this to us. Sayyiduna Abu Bakr al-Siddiq (may Allah be pleased with him) said: Are you going to follow the practice of Persia and Rome? No head is to be brought to me; a letter and a report are enough.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18351