Alignment Patterns of Romanesque Churches Dedicated to the Virgin of the Assumption in Soria, Spain

“Sol Aequinoctialis” and Sunrise on 15th August

Abstract

Previous studies have reported that in southern Spain some medieval churches are aligned to sunrise on the canonical equinox, independent of their dedication, and to sunrise on 15th August, for dedications to the Virgin of the Assumption. This paper aims to identify  precedents of this tradition in the province of Soria (northeast Spain), where the campaign by Christians to recapture territory held by the Muslims was accomplished in the first third of the twelfth century. This Reconquista was followed by a repopulation process and the building of a large number of rural churches in the Romanesque Repopulation style until the middle of the thirteenth century, many of which are preserved. The paper studies a set of 73 parish churches dedicated to the Virgin of the Assumption in Soria, with a subsample of 44 ascribed to the Romanesque. Their azimuths were measured from georeferenced orthophotographs. The normalised sums of probability densities have been computed for azimuths and declinations, and subjected to quantitative statistical assessment by using the confidence envelope curve and total peak area methods. The results reveal that 50% of the churches in the Romanesque subsample have intended alignment patterns. About two thirds of these were aligned toward the “sol aequinoctialis”, which can be evoked by (1) true east (astronomical equinox), and (2) sunrise on 21st or 25th March in the Julian calendar, the dates of the ecclesiastical and canonical equinox, respectively. The remaining third were aligned towards sunrise on 15th August. Data allows discussion on the accuracy in the involved practical methods used for alignments and on some relevant questions on the origin and spread of this tradition.