Juda b. Baba was pierced to death whilst found ordaining five elders against the decree of Rome: R. Jehuda, R. Simeon, R. Eleazar b. Shamua (and R. Avaye adds R. Nehemya).
Yehudah ben Bava Killed for Ordaining Five Rabbis
Gaster, Exempla of the Rabbis No. 68