Musannaf Ibn Abi Shaybah

Hazrat Abu Qabeel, may Allah have mercy on him, says that someone asked Hazrat Abdullah bin Amr, may Allah be pleased with him, whether Constantinople would be conquered first or Rome. Hazrat Abdullah bin Amr, may Allah be pleased with him, called for his box with rings and took out a book from it and began to read. Then he said that we used to sit around the Messenger of Allah, peace and blessings be upon him, and write. Once, he was asked whether Constantinople would be conquered first or Rome. The Holy Prophet ﷺ said that the city of Heraclius would be conquered first.