Chapter 1 offers an overview of the protohistory of the concept of parameter. The first part mainly focuses on the theoretical foundations of Generative Grammar, as laid out in Chomsky (1965). The discussion then turns to those works which paved the way to the parametric approach in Generative Grammar, with Chomsky (1973) introducing a first set of universal conditions on grammatical rules, and Chomsky (1976) being the generative work in which the term ‘parameter’ is used for the first time. The outcome of Rizzi’s (1978) and Taraldsen’s (1978) pre-parametric inquiries is then reviewed, as they shed new light on the systematicity of linguistic variation. Finally, focus is put on the explicit formulation of the concept of parameter and the consequent shift toward the systematic study of cross-linguistic variation, a problem previously addressed by Greenberg (1963). In this respect, the major advancement introduced by Chomsky (1981a) is the hypothesis of the existence of implicational relations among individual parameters. How the term ‘parameter’ is used in Chomsky and Lasnik (1977) in conjunction with the concept of core grammar is also discussed.