Far more interesting than this church, because much better preserved and because it is clearly derived, in part at least, from Batalha, is the cathedral of Guarda, begun by João I. Guarda is a small town, not far from the Spanish border, built on a hill rising high above the bleak surrounding tableland to a height of nearly four thousand feet, and was founded by Dom Sancho I. in 1197 to guard his frontier against the Spaniards and the Moors. Begun by João I. the plan and general design of the whole church must belong to the beginning of the fifteenth century, though the finishing of the nave, and the insertion of larger transept windows, were carried out under Dom Manoel, and though the great reredos is of the time of Dom João III. Yet the few chapels between the nave buttresses are almost the only real additions made to the church. Though of but moderate dimensions, it is one of the largest of Portuguese cathedrals, being 175 feet long by 70 feet wide and 110 feet across the transepts. It is also unique among the aisled and vaulted churches in copying Batalha by having a well-developed clerestory and flying buttresses. [Illustration: CATHEDRAL. GUARDA.] The plan consists of a nave and aisles of five bays, a transept projecting one bay beyond the aisles, and three apses to the east. At the crossing the vault is slightly raised so as to admit of four small round windows opening above the flat roofs of the central aisle and transepts. The only peculiarity about the plan lies in the two western towers, which near the ground are squares set diagonally to the front of the church and higher up change to octagons, and so rise a few feet above the flat roof. About the end of the fifteenth century two small chapels were added to the north of the nave, and later still the spaces between the buttresses were filled in with shallow altar recesses.