It is necessary to remember that the geographical barrier of the Pyrenees forms no real ethnological separation between that country and Spain; one and the same Iberian race dwells in Gascony, Navarre, and the Basque provinces. Hence it is easy to understand that natural relations, intimate and frequent, grew up between the two countries. Marriage alliances united the two royal families, and the princes of France crossed the frontier to fight against the Moors in Spain. With them came priests and monks, more learned than their neighbours, many of whom settled in the Peninsula. In this way the influence of the great orders of Cluny and Citeaux spread and grew powerful. Then followed architects and sculptors from Aquitaine, Languedoc, Toulouse, Burgundy, and Normandy, to find work, and impress their separate influences on the numerous churches that at this time were being built. The Romanesque cathedrals are indeed the direct outcome of French mediævalism; and the figure-statues of the numerous tombs and altars are full of reminiscences, so that it is difficult to distinguish the native art. Yet in the midst of these imported styles we shall find, do we seek them, those distinct traits which belong to Spain. It is in the province of Asturias that we find the greatest number of Romanesque churches. These churches were of moderate size. Their style was that of the basilica, with nave and aisles, a well-marked transept, a trans-apsidal termination, and a lantern or dome over the crossing. The roof was at first flat, but afterwards the nave was covered with barrel vaulting, and the aisles with quadrant or semi-barrel vaulting.