Saint Eustace (Latinized Eustachius or Eustathius, Greek Εὐστάθιος Πλακίδας Eustathios Plakidas)[1] is revered as a Christian martyr.

[3] The original tradition of the saint's passion is Greek, the oldest surviving version (BHG 641) was composed at some point during the 5th to 7th centuries.

When Trajan was succeeded by Hadrian, the new emperor asked his general to sacrifice to the gods, and when Eustathios refused, he threw him and his family to the lions, but the wild animals lay down at their feet.

Placidus is then awestruck by a vision where he sees the cross between the antlers of the deer, and in that moment, he is commanded by the voice of God to be baptized along with his family on that very night by the Bishop of Rome.

There in Rome, he was reinstated his original rank of general, led an army, and coincidentally, achieved victory in the home country of the captain who abducted his wife Theopista.

Trading life stories after the battle, two soldiers discover they were the brothers abducted by animals, and overhearing them, Theopista recognizes her husband Eustace.

Eustace and his family then return to Rome to celebrate at a victory dinner under the new Roman emperor Hadrian who was less tolerant towards Christians.

[6] Numerous adaptations of the saint's legend were composed, in verse and in prose, during the high medieval period, both in France and in Italy.

[7][8] The legend up to St. Eustace's martyrdom is a variant of the narrative type "the Man Tried By Fate", which is also popular in chivalric romance in general.

The historicity of Eustace cannot be substantiated, and he is widely seen as a "fictitious saint", i.e. an adaptation in the form of hagiography of what was originally a didactic or entertaining fiction.

46, p. 209) considers two possibilities: that of the saint being entirely fictitious, or that of an unknown early oriental martyr whose original cult has vanished without a trace.

[13] The origin of the Greek legend is most likely found in the Orient, likely Anatolia, perhaps Cappadocia, where the stag has long been venerated in local cults.

[15] A distant Indian origin for the element of the "separated family" has been proposed by Gaster (1893), specifically the Buddhist tale of Pacatara and Visvantara from the Pali canon (Dhammapada).

N. Thierry postulated that the tradition may have originated in Cappadocia, pointing out that a large repertoire of images of the Vision of Eustace exist as frescoes in this region's early-Christian rock-cut churches.

[14] In the West, an early medieval church dedicated to him that existed in Rome is mentioned in a letter of Pope Gregory II (731–741).

[19] Abbot Suger mentions the first relics of Eustace in Europe, at an altar in the royal Basilica of St Denis;[20] Philip Augustus of France rededicated the church of Saint Agnès, Paris, which became Saint-Eustache (rebuilt in the 16th–17th centuries).

Eustace became known as a patron saint of hunters and firefighters, and also of anyone facing adversity; he was traditionally included among the Fourteen Holy Helpers.

[21] He is the patron of hunters especially in Bavaria and Austria, while in France, Belgium and Western Germany, it is more common to find Hubert of Liège in this role.

Although the monastery was destroyed during the Armenian genocide, Thierry, in the 1980s, noted that a transmitted form of the legend still existed among local Muslim Kurds who talked of a "deer of light" appearing at the site.