Guarding and allowing entrance to the old town, the Gate of Santa Maria stands at the end of the Paseo del Espolón opposite the Puente de Santa María (bridge) spanning the Arlanzón River. The Arco de Santa María was originally built in the 14th century as a triumphal arch in honor of Emperor Carlos V. In 1552, the gate was renovated by Juan de Vallejo and Francisco de Colonia in Renaissance style. The massive arch is flanked by two semicircular towers, giving it the appearance of a castle. The gate features statues of Castilian heroes and kings: in the center of the lower row is Diego Porcelos, the town's founder, next to Nuño Rasura and Lain Calvo, the first judges of Castile; in the upper row are the Cid, the Emperor Charles V, and Count Fernán González. Walking through the arch, visitors will reach the Plaza del Rey San Fernando on the southern side of the cathedral. The interior is often used to display temporary art exhibitions.