A stained glass window that brings light to the church and pays tribute to one of the most famous martyrs, Saint Eulogius, elected archbishop of Toledo and intellectual. He lived during the time of the Islamic Emirate, although he traveled to the northern part of the peninsula, bringing knowledge with him. The author of several influential works in the thought of his time, he was martyred by decapitation in the year 859. All of this is represented in his attributes: episcopal attire, the palm of martyrdom, and the book of knowledge.