Chapter 3 examines the historical origins of the standing, cause of action, and damages ideas that are at the heart of this study. The focus is on decisions of ad hoc arbitral tribunals and ‘mixed claims commissions’ of the nineteenth and first half of the twentieth centuries, in particular the Venezuelan and Mexican Commissions of 1903 and 1923–1934 respectively. The chapter aims to understand the context and function of the concepts from which the current position on shareholder standing and international causes of action evolved. It concludes that mixed claims commissions and ad hoc tribunals were already attentive to and dealt with the effects of overlaps between national and international claims. This chapter suggests that contemporary investment tribunals should adopt a similar approach.