Abu Qabeel said: I heard Sayyiduna Abdullah bin Amr (may Allah be pleased with them both) say: We were sitting around the Messenger of Allah (peace and blessings be upon him) writing, when suddenly the Messenger of Allah (peace and blessings be upon him) was asked: Which city will be conquered first, Constantinople or Rome? The Noble Prophet (peace and blessings be upon him) replied: "No, the city of Heraclius will be conquered first." (That is, Rome).
Hadith Takhrijاس روایت کی سند قوی ہے۔ دیکھئے: [مصنف ابن أبى شيبه 329/5] ، [المعجم الكبير 61]
Brief Explanation
(Commentary on Hadiths 499 to 503)
From this, the writing down of hadith is established, and the prophecy of the Messenger of Allah (sallallahu alayhi wa sallam) is also proven to be correct.