Well, I'm not going to get my computer back until sometime next week (fully fixed and running great, I hope), so I am writing this from the library.
Ghirlandaio's painting, The Adoration of the Shepherds (click on the pictures to view enlarged verisons) is one of my favorites. You'll find it in
Santa
Trinita', a church just over the bridge from the flagship Ferragamo store. There is much to see in this church, but the altarpiece in the Sasseti chapel is definitely worth crossing the Arno for.
Domenico Ghirlandaio (his real name was Domenico di Tommaso Curradi di Doffo Bigordi--that is Domenico son of Tommaso who was son of Doffo)). Maybe it was just too long a name, but he was known as Ghirlandaio, that is garland-maker, after his father. Tommaso was a goldsmith who specialized in elaborate gold and silver garlands fashionable Florentine ladies wore on their headdressses.
Born in 1449, the same year as Lorenzo de' Medici (the Magnificent), Ghirlandaio was considered one of the finest artists of his day. He was a contemporary of Botticelli, and the two worked together on the Sistine Chapel in Rome. (Michelangelo only painted the ceiling, and there are many more frescoes on the walls). But unlike Botticelli who was an innovator, Ghirlandaio was highly influenced by painters from the north, especially Hugh van der Goes (you can see a wonderful example of his work in the Botticelli Room at the Uffizi). 
Francesco Sasseti (that's him on the right), who was the general manager of the Medici banking empire, commissioned
Ghirlandaio to do a whole series of frescoes in the chapel at Santa Trinita' depicting the life of St.
Francis of Assisi as well as the strikingly lovely altarpiece with portraits of Sasseti and his wife in panels on eit
her side.
The Adoration of the Shepherds was not a popular subject at this time. The Adoration of the Magi was
much more common. Ghirlandaio's and Sasseti's choice of this much more humble subject may have been in direct response to Gentile da Fabriano's magnificent golden Magi in the adjoining Strozzi chapel. (It now hangs in the Uffizi).
The Adoration of the Shepherds is based on Luke 2:16--"So they went with haste
and found Mary and Joseph, and the child lying in a manger." Hmm. Except in this painting the child is lying in front of a Roman sarcophagus. It is filled with hay that the animals appear to munch on, but it's no wooden manger.
Notice the Latin inscription on the sarcophagus--it explains the mystery. The words refer to a prophecy that a God will rise from the tomb of Pompey the Great. You'd have to know the whole story of Pompey, as the educated Renaissance men would have, to get the reference. But anyone could see that the Roman setting (note the columns in the background) symbolize the triumph of Christianity over paganism. This idea is further emphasized by the crude wooden roof that's precariously hanging atop the Roman columns: the humble Christ child and his followers prevail over the might of Rome.
I know. This doesn't really explain the mystery. But it does begin to give you a glimpse into the many layers of meaning that Ghirlandaio invested in every singe detail of this painting. I could write a book on it. But, today I'll just point out a few of the more interesting things.
Starting at the right of the painting, look at the dark haired man, pointing to himself and at the garland on the sarcophagus. That's Ghirlandaio's self-portrait, which he makes sure you "get" by connecting himself with the garland.
Next, the ox and donkey are symbols of the Jews and the Gentiles. In the foreground there's a solitary stone for Sasseti whose name means "little stone." The goldfinch perched nearby is a symbol of Christ's Passion and Resurrection.
It's hard to see in the reproduction, but there are two different cities on the hills in the background. The one on the right is Jerusalem (not, as you might expect, Bethlehem) and the one on the left is Rome. There's a dome in the Roman view that closely resembles the dome of the cathedral in Florence. Florentines of the time liked to style their city the "new Rome" for its power and prestige.
Mary looks serene and adores the fleshy baby lying naked on a corner of her cloak. But Joseph, who gazes off with his hand on his forehead, looks like he's wondering just what he's gotten into. In the background on the right you can see the Magi winding their way down the mountain, and above them are some sheep wandering freely. It seems their shepherds have run off after hearing the tidings of the birth from that angel overhead.
I hope you get a chance to this this painting in its original setting in church someday. it's so much better in real life.