More about prefatory
Prefatory “of or relating to something introductory” is based on the Latin noun praefātiō “a saying beforehand,” plus the adjective-forming suffix -ory. Praefātiō became Medieval Latin prēfātia and then became Middle French preface, which English has borrowed. In this way, prefatory and preface are doublets, two words in a language with the same origin but that took different pathways to get there—in this case, directly from Latin and by way of French, respectively. Latin praefātiō is a compound of prae “before,” which is the source of English pre-, and fārī “to speak,” which is the source of affable, fable, fate, and infant. Prefatory was first recorded in English circa 1670.