The Mytilene Gospel Book (Lesbos, Mytilene Boys Gymnasium, cod. 9) is an illustrated Greek manuscript, dating from the early thirteenth century. Illustrations in the Mytilene Gospel Book consist of a frontispiece (the Tree of Jesse), four Evangelist portraits, four headpieces at the beginning of each Gospel, and eighty-nine illustrations of the life of Christ. In this paper, unusual illustrations in the headpiece are focused on, where each Evangelist is combined with the second person and one of the three images of Christ (the Emmanuel, the Pantokrator, and the Ancient of Days). How were the three images of Christ related with the four Evangelists? Here, the Evangelist Matthew is accompanied by persons from the Old Testament who represent the past, Luke by the other Evangelists who represent the contemporary, and John by the angel who represents the future. Thus the epithet of Christ (the Lord who is, and who was, and who is to come) is laid to embellish the Evangelists. Furthermore, the frontispiece (the Tree of Jesse) expresses the genealogy of Christ, and together with the extensive narrative cycle, they emphasize the life of Christ on earth. On the other hand, the headpieces with the three images of Christ express the eternal life of Christ. Thus the unusual illustrations of the Mytilene Gospel Book visualize the two nature of Christ, the incarnated man on earth and God with the eternal life in parallel.