PREVIOUS TRADITION? COINCIDENCE? DESIGN? HOW IT WAS POSSIBLE TO CREATE THE ILLUMINATION EFFECTS AT THE CATHEDRAL OF SAINT JAMES (GALICIA, SPAIN)?

In a previous work based on different oral traditions collected at the beginning of the XX Century we verified that inside the cathedral of Saint James different illumination effects take place over the figure of Saint James located at the main altar, in particular at important dates related with Christianity and the own Saint. However, despite the fact that illumination effects occur and therefore suggest that they were sought and not a coincidence, we should ask how the builders of the cathedral could “create” them during the baroque reform of the cathedral. This is precisely the objective of this paper, to show how they could create this project of illumination or how they readapt a previous tradition that took place in the Romanesque building. To do that we count with different primary sources such as texts, drawings, ethnographic resources and cross-references. On a more methodological level, this is a study that deals with very different methods from diverse disciplines, such as archaeoastronomy or cultural astronomy, archaeology, architecture and ethnography. It is important to take into account, that the cathedral is an architectural project where the builders thought and planned a structure suitable for people in which the Christian imaginary had to be present, and therefore this illumination effects would play a very important role. However, such project was a living organism that evolved through time by the different reforms. Such reforms not only involved changes in the architectural styles but also in the concepts behind such styles. In particular it is important for our study how the concept and use of light within the temples changed along these centuries and how the light phenomenology was incorporated with a different meaning in the subsequent reforms. Finally, we recreate the possible method that the builders used based on architectural treatises