This article challenges the way côla and periods are delineated by exegetes involved in the so-called “sound mapping” approach. Specifically, the author argues that certain criteria for identifying côla and periods that are provided in both the initial version of the method outlined by Margaret E. Lee and Bernard B. Scott (2009) and the refined version proposed by Dan Nässelqvist (2015) conflict with the data from ancient sources. In other words, the criteria typically used for delineating côla and periods fail to accurately reflect the ancient conventions of structuring prose texts. Given the crucial role of the notions of côlon and period for the approach of “sound mapping,” further investigation into the rhetorical treatises from the Graeco-Roman world is warranted. Such an investigation, as this study aims to show, allows us to get a deeper understanding of the ancient system of colometry and to lay the foundation for a more historically-informed set of criteria.