In Ptolemy's Tables, the town appears as Aquae calidae and in the Itinerarium Antonini]] as Aquae Celenae. Lucas de Tuy calls it Caldas de Rege. F. Pérez calls it Cilenos or Celenae.
A bishop of this see named Ortigius was at the first Council of Toledo at the end of the 4th century. Of two bishops consecrated later, named respectively Pastor and Siagrius, one appears to have been for this diocese.