The legal foundation of international investment regulation (IIR) is vast, complex and varied, across numerous substantive and procedural rules. It is laid down in close to 3,000 different international investment agreements. This network of investment treaties is complemented by two key arbitration treaties: the 1958 New York Convention for the enforcement of arbitral award, and the 1965 ICSID Convention, which provides a forum and procedural rules for investment treaty arbitration. This complex landscape thus legitimately begs the question: how have we come to this network of legal instruments, and what do they entail?