This thesis explores the governance implications that historically accompanied arbitration between private and public entities – private-public arbitration (PPA). Modern international legal literature has increasingly started to view the most prominent present-day iteration of PPA – investment-treaty arbitration – as not just a mode of dispute resolution but as an important vehicle of (global) governance. Overwhelmingly, this realization has been accompanied by an assumption that this is a revolutionary development that significantly departs from previous practice. Consequently, despite the burgeoning scholarship on investment-treaty arbitration’s governance role, scholarly interest into whether other modalities of PPA historically operated as a mode of governance, prior to the advent of investment-treaty arbitration, has been lacking. The exploration of PPA’s historical role in governance that the thesis undertakes is largely based on original archival research conducted at various European and North American archives. The collected material has by and large not been previously analysed, or at least not within international legal literature. The analysed material reveals three primary modalities through which PPA’s historical governance role manifested itself. First, it was reflected in PPA’s capacity to influence the costs that accompanied public entities’ governance choices. Second, it was expressed through PPA’s capacity to direct how public entities were to exercise their official functions. And third, it was exhibited through PPA’s role in contributing to the development of the normative architecture governing private-public relations. The thesis thus concludes that, contrary to prevailing perceptions of the discipline, PPA has historically had a significant governance footprint.