This project investigates the nature of the Latin verb stems, based on the analysis of a corpus consisting of Classical and Late Latin historiographical texts. It examines their basic value: an aspectual opposition (perfectivity-imperfectivity) or a difference in relative tense (anteriority-simultaneity). The framework is a Systemic-Functional model with three semantic dimensions: ideational (propositional content), textual (foreground-background), and interpersonal (discourse mode).