This year marks 50 years since John Gunderson and Margaret Singer identified borderline personality disorder as a distinct psychiatric disorder, yet the history of the syndrome predates this pioneering work by several decades. Undoubtedly, the evolution of the borderline personality disorder construct occupies a position of great importance in the history of psychiatry; debates surrounding its nature, etiology, and diagnosis continue to fill the pages of psychiatric and psychotherapy journals around the world. This article seeks to provide a brief overview of the history of borderline psychopathology, from early descriptions of "borderline schizophrenia" to Gunderson's identification of borderline personality disorder and beyond. It focuses mainly on the evolution of psychoanalytic models of borderline personality disorder, including work by theorists such as Kernberg, Masterson, and Adler, but also covers Linehan's development of dialectical behavior therapy and more recent discussions regarding the relationship between borderline personality disorder and complex trauma. We argue that understanding the history of borderline personality disorder can enrich contemporary practice and inform current discussions regarding the disorder's nosological status.