Few have paid attention to the role that pan-Hellenic religious norms play in Thucy-dides‟s The Peloponnesian War. This thesis investigates the trope of religious sacrilege in the form of violated sacred space. By examining how this trope functions within his chosen rhetori-cal presentation, I will argue that a secular interpretation of Thucydides does not accord with what he tries to accomplish within his narrative, and that scenes describing such sacrilege actual-ly function in crucial ways to support a major premise of his work. Two specific instances of sacrilege will be examined: the civil war on Corcyra in 427 BCE; and the Battle of Delion in 424/3 BCE. I will demonstrate that Thucydides incorporates sacrilege to serve as evidence for his readers that the Peloponnesian War was the worst war the Greek-speaking world had everexperienced, and that religio-cultural norms, however unanimously conceived and internally ob-vious, are inherently fragile and unstable.