José Alonso stood out as a mathematician. In 1800, the archbishop of Santiago asked him to make up the geographical and statistical map of the archdiocese. He was elected deputy in 1812. Two years later he was persecuted for his liberal ideas and had to go into exile.
During the exile he wrote in six volumes the work Consideraciones generales sobre varios puntos históricos, políticos y económicos a favor de la libertad y fomento de los pueblos, y noticias particulares de esta clase relativas al Ferrol y su comarca (1820).