Mundhir al-Thawri said: Whenever we mentioned Husayn and those who were martyred with him, Muhammad bin al-Hanafiyyah would say: "Seventeen young men were martyred with him, all of whom had been nurtured in the womb of Sayyidah Fatimah (may Allah be pleased with her)."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 2842