It is narrated from Sayyiduna Bishr bin Suhaim (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: "Constantinople will certainly be conquered; its commander will be the best commander and that army will be the best army." Abdullah says: Maslamah bin Abdul Malik called me and asked me about this, so I narrated this hadith to him, and because of this, he launched an expedition against Constantinople.
Hadith Takhrij«اسناده ضعيف لجھالة عبد الله بن بشر الخثعمي، أخرجه الحاكم: 4/ 421، والطبراني في الكبير : 1216، (انظر مسند أحمد ترقيم الرسالة: 18957 ترقیم بيت الأفكار الدولية: 19165»
Abu Qabeel says: We were sitting with Sayyiduna Abdullah bin Amr bin Aas (may Allah be pleased with him) when he was asked which of the two cities, Constantinople or Rome, would be conquered first. He called for a box with hinges, took out a book from it, and said: Once we were sitting around the Messenger of Allah (peace and blessings be upon him) writing down ahadith, when the same question was asked to the Messenger of Allah (peace and blessings be upon him): Which city will be conquered first, Constantinople or Rome? The Messenger of Allah (peace and blessings be upon him) replied: The city of Heraclius, that is, Constantinople, will be conquered first.
It is narrated from Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him), the Messenger of Allah (peace and blessings be upon him) said: Great bloodshed, the conquest of Constantinople, and the appearance of the Dajjal—these three events will manifest within seven months.
Hadith Takhrij«اسناده ضعيف لضعف ابي بكر بن عبد الله بن ابي مريم والوليدِ بن سفيان بن ابي مريم، ولجھالة حال يزيد بن قطيب، أخرجه ابوداود: 4295، والترمذي: 2238، وابن ماجه: 4092 ، (انظر مسند أحمد ترقيم الرسالة: 22045 ترقیم بيت الأفكار الدولية: 22395»
It is narrated from Sayyiduna Abdullah bin Busr (may Allah be pleased with him), the Messenger of Allah (peace and blessings be upon him) said: There will be a gap of six years between the great bloodshed and the conquest of Constantinople, and in the seventh year the Dajjal will appear.