He is master Yehya the son of al-Qasem al-Tayyeb, the son of Mohammed al-Ma`mun, the son of Ja’far al-Sadeq, the son of Mohammed al-Baqer, the son of ‘Ali Zayn al-Abidin; he is Fatima al-‘Ayan’s brother.
He was called ‘the one who resembles the Prophet’ because he took after his grandfather in looks and characteristics, sublimity and dignity, and generosity and bravery. He was known for his scholarship and blessings. He was summoned to Egypt by Ahmed Ibn Touloun to appease the Egyptians due to his benevolence and because the Egyptians are known for their sincere love for Ahl al-Bayt and for their loyalty to them.
The day on which he entered Egypt with others from among the Ashraf was a great feast day for the Egyptians.
(His shrine is near Imam al-Shafi’i)