According to legend, prior to his conversion to Christianity, Eustace was a Roman general named Placidus, who served the emperor Trajan. While hunting a stag in Tivoli near Rome, Placidus saw a vision of a crucifix lodged between the stag's antlers. He was immediately converted, had himself and his family baptized, and changed his name to Eustace.wiki
A series of calamities followed to test his faith: his wealth was stolen; his servants died of a plague; when the family took a sea-voyage, the ship's captain kidnapped Eustace's wife Theopista; and as Eustace crossed a river with his two sons Agapius and Theopistus, the children were taken away by a wolf and a lion. Like Job, Eustace lamented but did not lose his faith.
He was then quickly restored to his former prestige and reunited with his family; but when he demonstrated his new faith by refusing to make a pagan sacrifice, the emperor, Hadrian, condemned Eustace, his wife, and his sons to be roasted to death inside a bronze statue of a bull or an ox, in the year AD 118.
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.
The saint's cross-and-stag symbol is featured on bottles of Jägermeister. This is related to his status as patron of hunters; jägermeisters were senior foresters and gamekeepers in the German civil service at the time of the drink's introduction in 1935.
I in fact had some last evening, not because of the vigil, but because I have a nasty cold. Seriously, I'm convinced the stuff could cure leprosy.