The Historical Development of “Amicus Curiae” and the Reasons for Its Emergence

This chapter traces the historical evolution of the Amicus Curiae practice, from its possible origins in Roman law to its development in the English common law system and eventual flourishing in the United States. While the amicus role may have roots in the Roman legal advisor tradition, it solidified within the adversarial context of English courts, where amici assisted unrepresented defendants, provided expertise to judges, and helped prevent errors. As the practice migrated to the United States, it further evolved to allow representation of third-party interests and, by the twentieth century, became a major tool for advocacy organizations to influence public interest cases. Though perspectives differ on whether a shift occurred from neutral “friendship” to advocacy, the adaptable amicus role has proven vital in shaping substantive rights. The chapter concludes that despite its procedural form, the amicus practice embodies the societal impact of law.