St. Agnes by Domenichino, ca. 1620.
Today is the feast of St. Agnes of Rome, a young martyr, who not only has two significant Churches dedicated to her in Rome, but whose name is in the Roman Canon. Indeed, 28 January is also known as her "second Feast." As the Old Catholic Encyclopedia notes: "On her feast two lambs are solemnly blessed, and from their wool are made the palliums sent by the Pope to archbishops."
St. Agnes was a young, about 13 year-old, Christian, who refused to renounce her Faith, or surrender her purity, in the face of a Roman persecution (some sources argue it was the Decian persecution, but the consensus seems to be that of Diocletian). She was condemned to be taken to a brothel at the Circus of Domitian (now Piazza Navona) in the Campo Marzio, only to be miraculously preserved from rape. That site was marked and became the basilica of Sant'Agnese in Agone in 1123 (this currently houses the relic of her skull). That basilica would be magnificently renovated in the 17th century by Baroque artists including Francesco Borromini and Gian Lorenzo Bernini. Despite the preservation of her purity, she would be executed by her persecutors. Another basilica was constructed over her grave outside the walls of Rome during the time of the Emperor Constantine, this being Sant'Agnese fuori le mura.
It is worth noting that St. Thomas Aquinas, the 13th century Dominican and Doctor of the Church, had a great devotion to St. Agnes.
Here are a couple links with more about this great martyr for purity:
Golden Legend: On St. Agnes
Old Catholic Encyclopedia: St. Agnes of Rome
Catholic Saints Info: St. Agnes of Rome
Customs associated with St. Agnes (Fisheaters)
Basilica of Sant'Agnese in Agone on Piazza Navona.
Here are links to the websites of the two Churches in Rome bear her name: Sant'Agnese in Agone on Piazza Navona, the site of her agony at the brothel, and current location of the relic of her skull: Sant'Agnese in Agone official site
The interior of Sant'Agnese fuori le mura.
["Sant'Agnese fuori le mura - interno - dal matroneo" by Parrocchia di Santa Agnese fuori le Mura - http://www.santagnese.org/galleria_foto.htm. Licensed under CC BY-SA 2.0 via Commonsg]
Sant'Agnese fuori le mura, where she is buried: Basilica of Sant'Agnese fuori le mura official site
Father Zuhlsdorf had a splendid post from a couple years ago on the blessing of the lambs by the Holy Father on the Feast of St Agnes: Fr. Z's Blog: Francis and the Lambs
Live well, and be pure!