Epi-Olmec culture in the context of "Isthmian script"

Tres Zapotes is a Mesoamerican archaeological site located in the south-central Gulf Lowlands of Mexico in the Papaloapan River plain. Tres Zapotes is sometimes referred to as the third major Olmec capital (after San Lorenzo Tenochtitlán and La Venta), but the Olmec phase is only a portion of the site's history, which continued through the Epi-Olmec and Classic Veracruz cultural periods.

The 2000-year existence of Tres Zapotes as a cultural center is unusual, if not unique, in Mesoamerica.

Olmec hieroglyphs are a set of glyphs developed within the Olmec culture. The Olmecs were the earliest known major Mesoamerican civilization, flourishing during the formative period (1500–400 BCE) in the tropical lowlands of the modern-day Mexican states of Veracruz and Tabasco. The subsequent Epi-Olmec culture (300 BCE to 250 CE), was a successor culture to the Olmec and featured the Isthmian script, which has been characterized as a full-fledged writing system, though with its partial decipherment being disputed.

There is no scholarly consensus whether Olmec hieroglyphs represent language, or are a system of proto-writing; the possible existence of writing during Middle and Late Olmec periods has been a matter of long-standing debate. Direct evidence includes the appearance of individual (potential) glyphs as well as the singleton Cascajal Block that bears a potential text. Indirect evidence includes similarities in calendar and writing systems between subsequent Mesoamerican cultures, for which the Olmecs are sometimes considered a mother culture.