Romanesque and Gothic architecture are closely linked to the precepts of the Church. Following the church reform of the X century, propelled by William of Aquitaine's initiative to free the Order of Cluny from any secular or regional ties by placing it directly under the rule of the Papacy, the Benedictine rule became the dominating tendency in western Christianity.
But from round about 950 AD to well into the XI century, the religious establishment saw a tide of immoral, abusive and corrupt behaviour spread across both its local and regional semi-autonomous institutions, and the centre of power in Rome. The result was an erosion in the respect it commanded and a clear loss of its political power over the secular body of governance across the continent.
This is the environment that led to the next church reform, the Gregorian , which sought a return to the virtuous life of the early Apostles, returning the Church to a moral standard that would allow it to claim the high ground, ensuring a much more stringent centralisation of the clerical institution, and ensuring the division of secular and religious powers, whereby the secular would be evidently lower in rank than the religious, though not necessarily dependant on it.
The church reform of the end of the XI century placed stronger emphasis on the two elementary activities that would promote the pious life on Benedictine priests: prayer and manual labour. Thus, two important orders emerged towards the end of the XI century that, in stark contraposition to the luxury enjoyed by Cluny, would promote a different lifestyle and would give rise to Gothic architecture. They were the Carthusian Order, and, most importantly, the Cistercian Order.
Established in 1098, the Cistercian Order reached prominence through the arduous work of Bernard of Clairvaux, a courageous and eloquent mystic who turned the order's message of austerity, temperance and piety into an international motto. Where Cluny had succeeded by promoting trade, developing the economy and establishing important regional centres, the Cistercians hit back with a rural sort of clergy, unafraid to to permeate the most recondite and dangerous areas.
The Cistercian Order became the main propagator of a new ethic code that was mirrored in the aesthetic changes that would lead to the transition from the solid Romanesque to far lighter Gothic architecture. Among the primary differences from the High Romanesque style and the later, transitional, constructions counts a clear intention to subdue the monolithic characteristics of the earlier buildings, most commonly through the enlargement and opening of windows.
Thus, towards the end of the XII century some buildings in Spain display a combination of semicircular and pointed arches. For instance, the Church of St Vincent in Ávila, features a rich blend of clearly Romanesque characteristics in its three circular apses, blind arches decorating the roofs and semicircular windows on the nave of the church, while the main doorway and a number of other windows use the pointed arch that soon will become the trademark of Gothic architecture.
Similarly, the Cathedral at Ávila displays some Romanesque elements, remnants of the ancient style, which contrast heavily with the primarily Gothic structure of the building. Originally designed as a massive nave with a single apse, the semicircular shape of the latter with its small windows is an unequivocal sign of its Romanesque origins, strikingly more conservative than the flying buttresses that hold it.
Another good example of a transitional building is found in the Cathedral of Santo Domingo de la Calzada, which still today, despite the rigorous reconstruction withstood by the building centuries later, offers a beautiful view into the simplicity of Romanesque lines in its semicircular apses, cut slightly by minute windows and held firm by buttresses that support the flying buttresses of the higher levels of the building.
Slowly the age of the Romanesque was coming to an end, both in aesthetic and cultural grounds. And yet, even today, the legacy of these times and its buildings is well worth revisiting, especially given they many of them are so close to the capital you could easily just go for a day.