Scottish painter John Duncan (1866-1945) established his early style with paintings based on Arthurian legend; then he applied himself to Celtic myths and legends to create a series of paintings that are unique among early-twentieth-century Scottish art. While the Symbolist movement was probably his most important source of inspiration, his paintings were imbued with the spirit of the Italian Renaissance, and he spent much of his life experimenting with various compositions of tempera in order to obtain the precise density of color and smoothness of surface that characterize his work. The author outlines Duncan's technical, intellectual, and spiritual development as an artist and his close association with Patrick Geddes, the botanist and socialist who was devoted to a renaissance of Celtic art and who was instrumental in Duncan's commitment to the same. Duncan eventually created a unique body of work rich in Celtic legend and ornament and steeped in the tradition of the Byzantine style.