Ad orientem: Romanesque Churches of the French Way in the kingdoms of Castile and Leon from a Cultural Astronomy perspective

This paper examines whether the Romanesque churches of the Way of Saint James or Camino de Santiago follow a common orientation pattern from the perspective of Cultural Astronomy. In order to do so, the orientation of 191 Romanesque churches in the former kingdoms of Leon and Castile has been obtained and a comparative study has been carried out. Both kingdoms share the orientation toward the sunrise on Easter Sunday, probably obtained by direct observation of the Sun over the horizon. However, Leon shows a strong preference for the ecclesiastical equinox of March 21, which does not appear in Castile. Churches belonging to the Way and a contrast sample at each kingdom have been also compared, providing relevant information about some churches built at specific places such as Santiago de Compostela, Ribeira Sacra, Sahagon or the Montana Palentina.