Abstract
The present paper deals with the examination and research to the vestiges of an ancient church discovered in the basement of the Algemesí Communion Chapel, dating back to the beginnings of Christianity in the city. Considering the disposition of the constructive elements and the documented historical facts that date back to the first parish in the 13th century, it was deduced that the remains found were part of a temple with diaphragmatic arches and a woody roof. These facts are the paradigm of the ecclesiastical architecture that prevailed, by its execution speed, in the kingdom of Valencia after Jaime I reconquest. The study includes the comparison with other buildings of the same nature that allowed reconstructing its hypothetical volume, as well as the analysis of the techniques and materials that shaped its structure. Its identification ascribes another example to the Valencian protogothic architecture.