Urwah (may Allah have mercy on him) states, among the names of those who were martyred on the day of Uhud, from the Ansar, then from Banu Sa'idah: Tha'labah bin Sa'idah bin Malik bin Khalid bin Tha'labah bin Harithah bin Amr bin al-Khazraj.
Hadith Referenceالمعجم الكبير للطبراني / باب الثاء / 1379