In this article, we analyse the characteristics of the grammaticalization process that originates connectors, taking as analysis corpus the book «Costums de Tortosa». We have identified the temporal forms that became interordinate connectors (causal, consecutive, concessive, conditional and adversative), and have outlined the characteristics of the semantic change and of the sintactical reanalysis which can be observed in this process. As an example of this general process, we have analysed the semantic change in the case «encara» / «encara que» and the sintactical reanalysis in the semifixed structure «jasia ço que».