To what extent is the hadith authentic: "There will be a man from Banu Umayya in Egypt, with a flat, broad nose, who will wield authority that will be overcome or seized from him, so he will flee to the Romans. He will then bring the Romans against the people of Islam, and that will be the first of the great battles (al-Malahim)"?

The aforementioned hadith (definition) is weak. It was narrated by Al-Ruyani and Ibn Asakir from Abu Dharr (may Allah be pleased with him) with the wording: "There will be in Egypt a man from Banu Umayyah, akhnas (with a flat nose), with a contracted nose bridge and a wide nostril. Then he will be overcome, or it will be taken from him, and he will flee to the Byzantines. He will then bring them to Alexandria, and he will fight the Muslims there. That will be the first of the great battles." Ibn Asakir declared it deficient, and Al-Dhahabi affirmed it, and Al-Albani declared it weak.