This course aims to familiarize students with a) the reception of Platonic, Peripatetic and Neo-Platonic geometrical metaphors, particularly the circle and radii metaphor, in late Antique and medieval, especially Byzantine authors, b) the visual representations of the circle and radii metaphor in the Greek, Latin and Slavonic manuscripts, c) the Neo-Platonic, or particularly Dionysian metaphor of light, and its reception in the later Byzantine authors, as well as Byzantine visual art and architecture. In the first part of the course, the focus will be on reading the selected primary sources (in English) of Platonic (Euclid, Alexander of Aphrodisias) Neoplatonic (Plotinus, Proclus, Damascius) and Greek and Latin Christian authors (Clement of Alexandria, Boethius, Dionysius the Areopagite, Dorotheus of Gaza and Maximus the Confessor) employing the circle and radii metaphor. In the second part of the course the focus will be shifted to particular diagrams depicted on the layouts of the Greek, Latin and Slavonic manuscripts. Since the analyzed diagrams that accompany the copied text range from very simple depictions of circle and radii to very complex images, the focus will be on different elements, such as the circle’s centre, circumference, radii as well as additional visual elements. In the third part of the course the focus is shifted from the circle metaphor in the manuscripts to the circle metaphor, visualized in the forms of aureole and the mandrola in the Byzantine, and medieval Latin and Serbian art. The symbolism and mysticism of light, closely connected with the circle metaphor, is particularly studied in Symeon the New Theologian through his understanding of ecstasy and Gregory Palamas through his understanding of stillness (hesychia). Since the scholarly analysis is equally divided to work with texts and images, the course is relevant for students in classics, late antique and medieval studies, philosophers and art historians.