Construction of the Cathedral started in 1075, when the town arrived to the climax of its importance. The chapel, Capilla del Salvador, is still conserved of this oldest epoch.
The second phase, after the wedding of Doña Urraca and Raimundo of Bourgogne, shows influences of french Romanesque style, as well as a style that is all Santiago's own, the so-called Románico Compostelano. The Obradoiro Facade (to which lateron were added Barroque elements) and the towers Torre de las Campanas and Torre
Through the Obradoiro Door you enter the so-called Old Cathedral, a Romanesque crypta with the first vaults of groined arches that were ever built in Spain.
The sculptures of the Portico de la Gloria, another entrance door, are considered some of the most important works of medieval art.
It has never played a large part in the medieval architecture courses I have taken and taught, perhaps because it is a mixture of styles. I'm also not a great fan of the busy Baroque style, so that's a second reason that I (probably unfairly) ignore it. I usually just use it to talk about the pilgrimage routes.
Did your daughter like her visit there?
I need to put her pics up because they're fabulous.