She is commemorated on July 20th in the Personal Ordinariate of Our Lady of Walsingham. Although she is an actual martyr, almost all the stories about her are apocryphal. In fact, in the year 494 Pope Gelasius I cautioned the Faithful about some of the fantastic stories which had grown up around her.
What is historical is that she was a native of Antioch-in-Pisidia, and was the daughter of a pagan priest. Her mother died soon after giving her birth, and she was then nursed by a pious Christian woman. Margaret embraced the Christian faith and was disowned by her father, after which her Christian nurse adopted her. She was asked by a local official to marry him, but she would have to renounce her Christian faith. Refusing to do so, she was tortured and eventually beheaded in 304.
Although many of the stories which grew up around the accounts of her torture were fanciful, (including a story of her being swallowed by Satan in the shape of a dragon, from which she escaped alive when the cross she carried irritated the dragon's innards), nonetheless there is still spiritual truth to be gained from these wondrous accounts.
The icon pictured here illustrates the story of a demon approaching her in her prison cell, attempting to convince her to renounce her faith. According to the story, a hammer was at hand, which she picked up and beat the demon senseless. I like this picture, and I think it serves as an icon of where we are now. Demons are nipping at us, and we can either give in or we can take the revealed Truth which has been given to us and we can use it to beat the stuffing out of satan and his demonic little friends.
Devotion to St. Margaret of Antioch was greatly strengthened during the crusades, when soldiers would hear stories of local saints and then bring them back to their homelands. Devotion to her became widespread in England, where more than 250 churches are dedicated to her, most famously St. Margaret's, Westminster, the church of the British Houses of Parliament in London. St. Margaret is one of the Fourteen Holy Helpers, and is one of the saints who spoke to Joan of Arc.
Even though this remarkable young woman is no longer commemorated in the general liturgical calendar, we can still look to her as a marvelous example and as an intercessor for us in these difficult days.
Grant, O Lord, that, like as blessed Margaret, thy Virgin and Martyr, by the merits of her chastity and the godliness of her conduct, did ever walk acceptably in thy sight: so she may at all times effectually intercede for our forgiveness; through Jesus Christ thy Son our Lord, who liveth and reigneth with thee, in the unity of the Holy Spirit, ever one God, world without end. Amen.