The article focuses on the comedy No hay reino como el de Dios y martires de Madrid, written in collaboration between Jeronimo de Cancer and Velasco, Juan de Matos Fragoso, and Agustin Moreto. The preliminary task is to distinguish this piece, taking into allow the manuscript and printed texts, from another with which it has been often confused, with reason of the similarity of argument and title: Dejar un reino por otro y martires de Madrid, which can reasonably be attributed to Cristobal de Monroy y Silva. Next, we try to find out the effective authorship of both acts, based on criteria of metric type.