This chapter provides an introduction to investigating supranational aspects of the ECHR. It examines how the ECtHR gradually transformed from an international into a supranational court. A legal-historical perspective is adopted to analyze the (institutional) developments and reforms of the Convention system and re-visit some of the well-known classics of (early) Strasbourg case-law. While tracing the transformation from international to supranational adjudication overlaps with and confirms existing narratives of incremental de-politization, judicialization and individualization of the ECHR system, this chapter connects existing accounts on the institutional evolution of the Convention system to an overall narrative and a broader conceptual framework. It submits that, although supranational adjudication is primarily the result of Protocol 11 and thus rests on a formal choice and commitment of contracting states, the special nature of the Convention as a human rights treaty exercised a particular pull towards supranational adjudication. As a result, the Court and the Commission early on distinguished the collective protection system under the Convention from interstate and state-controlled adjudication by conceiving of themselves as adjudicators of a community.