The church, cloister and atrium of Acolman, Mexico, form an architectural group that was built by the friars of the order of Saint Augustine in the early 16th century, a few years after the official consummation of the Spanish Conquest in 1521. It is a monastic-military construction decorated with reliefs and mural paintings that clearly reflect the objective of Christianizing the native population. The facade of the church has a plateresque style with a complex composition: columns with great decoration, sculptures of Church Fathers, cherubs, flora and fauna elements carved on stone. A row of representations of hybrid animals with marine and terrestrial characteristics, interpreted as seahorses or hippocampi was engraved under the frieze stands. The rarity of these elements led to the historic search for its iconographic meaning, finding its oldest sense in Phoenician culture, taken up by the Greek pagan bestiary, later resumed in Rome and from there it was taken up by Christianity that finally moved them to American lands through the Spaniards. The purpose of this document is to describe these fictitious marine beasts, to understand their ancient meaning and their role in the context of the first years of Catholic evangelization in Mexico that led to a process of religious syncretism that prevails until today. The method consisted of fieldwork in the locality of Acolman to study these elements; the theoretical research was based on bibliographic sources on history, art, architecture, and iconography. The results are published for the first time in this paper, clarifying that there is no specialized study on the topic of Acolman´s hippocampi in the literature. The research is part of the project Cultural-Historical Evaluation of the Collection of Paintings of the Ex Convent Museum of Acolman, State of Mexico, attached to the National Institute of Anthropology and History, which started in 2015 and has continued up to date.
