Eustathius or Eustace of Mtskheta (Evstat'i Mtskhet'eli; Georgian: ევსტათი მცხეთელი) (died c. 550) is an Orthodox Christian saint, executed for his apostasy from Zoroastrianism by the Sasanian military authorities in Caucasian Iberia (Kartli, eastern Georgia).

[1] Eustathius is reported by the hagiographer to have been an Iranian cobbler originally called Gvirobandak, son of a high-ranking Zoroastrian priest (magi), from Ganzak.

The local Iranian cobblers’ guild denounces Eustathius to the marzban Arvand Gushnasp with seven other converts to be judged.

Six months later, Arvand releases them, however, as a farewell gesture to the local people, when recalled from Georgia by the king Khosrau I.

Four years later, under the new marzban Vezhan Buzmihr, Eustathius is rearrested, but reaffirms his faith before the court in a speech of some 3,000 words that makes up nearly half the Passion.