Such a division does not, however, explain the historical development of the Christian kingdoms from the eighth to the fifteenth centuries, nor is it advisable to adopt it for an architectural study.
During the great period of church-building, the nine kingdoms of Spain formed four distinct groups: Galicia, Asturias, Leon, and Castile; Navarra and Aragon; Barcelona and Valencia; Andalusia.
The first group gradually evolved until Castile absorbed the remaining three kingdoms, and later Andalusia as well; the second and third groups succumbed to the royal house of Aragon.[{67}]
From an architectural point of view, there are three groups, or even four: Castile, Aragon, the Mediterranean coast-line, and Andalusia. In the last three the Oriental influence is far more pronounced than in the first named.
Further, Spain is divided into nine archbishoprics: four corresponding to Castile (Santiago, Burgos, Valladolid, and Toledo); one to Aragon (Zaragoza); two to the Mediterranean coast (Tarragon and Valencia); and two to Andalusia (Sevilla and Granada).
It was the author's object to preserve as far as possible in the following chapters and in the general subdivision of his work, not only the geographical, but the historical, architectural, and ecclesiastical divisions as well. Better still, he sacrificed the first when incompatible with the latter three.
But—and here the difficulty arose—what title should be chosen for each of the two volumes which were to be dedicated to Spain? Because two volumes were necessary, considering the eighty odd cathedrals to be described.
"Cathedrals of Northern Spain" as opposed to "Cathedrals of Southern Spain"—[{68}]was one of the titles. "Gothic cathedrals of Spain"—as opposed to "Moorish Cathedrals of Spain"—was another; the latter had to be discarded, as only one Moorish mezquita converted into a Christian temple exists to-day, namely, that of Cordoba.
There remained, therefore, the first title.
The first volume, discarding Navarra and Aragon (in the north), is dedicated to Castile, as well as its four archbishoprics.