Sayyid al-Shuhadāʾ (Arabic: سید الشهداء), which literally means "the master of martyrs", is the epithet the noble Prophet (s) gave to his uncle, Hamza b. 'Abd al-Muttalib, who was martyred in the battle of Uhud and mutilated. This is also one of the most famous epithets of Imam al-Husayn (a). This epithet was given to Imam al-Husayn (a) after his martyrdom. However, even before his martyrdom, some narrations by the Prophet (s) refer to him by this title.
It seems that this epithet became widely popular for Imam al-Husayn (a) during Imam al-Sadiq's era. One of the female companions of Imam al-Sadiq (a), an Iraqi woman called Umm Sa'id al-Ahmasiyya, had decided to visit the graves of the martyrs of Medina, when Imam al-Sadiq (a) asked her, "Why don't you visit the grave of the Sayyid al-Shuhada' of your own [town]?" Umm Sa'id, thinking that Imam al-Sadiq (a) is referring to Imam 'Ali (a) asked, "Who do you mean by Sayyid al-Shuhada'?" He replied, "Sayyid al-Shuhada' is al-Husayn b. 'Ali (a)."
Explaining how both Hamza and Imam al-Husayn (s) have received the epithet, Mulla Salih Mazandarani says that Hamza was the Sayyid al-Shuhada' of his time, whereas Imam al-Husayn (a) is the absolute Sayyid al-Shuhada'. After Hamza's martyrdom, Lady Fatima (a) made a Misbaha from his grave's soil and used every knot to say a dhikr in her prayers. Now Shi'as make Misbahas from Imam al-Husayn's (a) soil (see: Turba). Regarding the distinct quality of a Misbaha made from Imam al-Husayn's (a) soil, as compared to Hamza's soil, Imam al-Sadiq (a) says, "A Misbaha made of Imam al-Husayn's soil is blessed with the rewards of dhikr for only being onto one's hand even if he (the holder) himself is not uttering anything ." Read more...