What is another word for "forerunner"?

Roget's Thesaurus (1911) lists these synonyms for "forerunner": antecedent, avant-courier, bellwether, dawn, exordium, foreboding, foreword, frontispiece, groundwork, harbinger, heading, herald, inaugural, introduction, introductory, leader, omen, outrider, overture, pioneer, preamble, precedent, precursor, precursory, predecessor, preface, prefatory, prefigurement, prefix, preliminary, prelude, preludious, prelusive, prelusory, preparation, principle, prior, prodrome, prodromous, prodromus.