Abstract
This chapter draws on Roman law to build a new descriptive and analytical framework based upon the ideas of windows, (de)coders and travellers with a view to confronting contemporary understanding of private international law and public international law. We seek to identify in legal thought and practice common denominators between these disciplines in terms of methodology and legal reasoning. In shedding light on convergences between these two areas of international law, we will show that, in many respects, they are not distinct from one another, thereby suggesting that they rest on common methodological patterns.