Leaders of Babylonian Jewry, who were arrested by Persian officials, sparking a wave of persecution of the Jews of Babylonia. They were executed in Pumpedita, 470 CE., on the same day.
The Iggeret (letter) of Rabbi Sherira Gaon records that Huna bar (son of) Mar Zutra and Mesharshya bar Pakod were executed on the 18th of Tevet, 470 CE.
Rabbi Mesharshya bar brei (son of the son of) d' Rabbi Acha bar Rav may be the Mesharshya that Rabbi Sherirah Gaon was referring to.
May the merit of the tzaddikim Rabbi Huna bar Mar Zutra & Rabbi Mesharshya bar Pakod protect us all, Amen.