The architectural interest in parametric design has grown dramatically in the last few decades. However, there is a confusion between parametric and digital architecture, as a result of the conflict in defining the parametric architecture roots. Moreover, this research aims to settle on the origins of parametric architecture, and define the most important factors that influenced the development of it, assuming that the emergence of digital tools has the greatest impact on it. In this regard, the history of parametric architecture was divided into two historical eras: the first is the pre-digital era, and the second is the digital era. In each era, the most prominent parametric projects were reviewed and analyzed to deduce the most important evolution features in terms of capabilities, goals, characteristics, scale, and phase of application for both of eras and conclude the impact of digital tools on parametric architecture. It was found that the roots of parametric architecture go back thousands of years, but it has developed greatly, and the digital tools had the most influence on this development. Despite this, the pre-digital era cannot be considered as a single phase as it passed through two main phases, which differ greatly in characteristics.