The period between Justinian and iconoclasm saw major changes in the social and religious roles of images within Byzantium. The veneration of acheiropoieta, or holy images "not made by human hands," became a significant phenomenon, and in some instances these images were credited with saving cities from military assault. By the end of the seventh century, certain images of saints had come to be viewed as "windows" through which one could communicate with the figure depicted. Proskynesis before images is also attested in texts from the late seventh century. These developments mark the beginnings of a theology of icons.