This chapter addresses the motivation for the emergence of classifiers. Before Middle Chinese, there was no such category as “classifier” in the grammar of the Chinese language, and this word “classifier” was historically innovated. Individual classifiers started to emerge as early as Late Old Chinese, and the number of classifiers steadily increased over time. However, the rigorous grammatical rule that required a proper classifier for every numeral phrase was firmly established around the fourteenth century AD. Importantly, there was a parallel development of nominal and verbal classifiers; that is, verbal classifiers came into existence not long after the emergence of nominal classifiers.