1. For the same reason, the references offered here are indicative only.
2. Neils Hannestad, Roman Art and Imperial Policy (Aarhus: Aarhus University Press, 1988), 226–36 (Marcus Aurelius); 262–7 (Septimius Severus); 332–8 (Theodosius). For the centrality of victory to the Roman mindset, see Susan P. Mattern, Rome and the Enemy: Imperial Ideology in the Principate (Berkeley: University of California Press, 1999), 162–210.
3. Lactantius, De mortibus persecutorum 5.3–7 (Corpus Scriptorum Ecclesiasticorum Latinorum 27.2: 178–9).
4. Beate Dignas and Engelbert Winter, Rome and Persia in Late Antiquity: Neighbours and Rivals (Cambridge: Cambridge University Press, 2007), 77–82.
5. For an overview, see James S. Romm, The Edges of the Earth in Ancient Thought: Geography, Exploration, and Fiction (Princeton, NJ: Princeton University Press, 1992). The persistence of classical geographical norms can be gauged in a variety of Christian texts, such as Orosius' Histories Against the Pagans and the quasi-Christian Expositio totius mundi et gentium: see Hervé Ingelbert, Interpretatio Christiana. Les mutations des savoirs (cosmographie, géographie, ethnographie, histoire) dans l'Antiquité chrétienne, 30-630 après J.-C. Collection des Études Augustiniennes, Série Antiquité 166 (Paris: Institut d'Études Augustiniennes, 2001), 25-192