Construction began in 1749 of a circular ring on Baratillo Hill to replace the rectangular bullring that was previously located there. In 1761, the construction began to incorporate "ochavas" (each "ochava" being equivalent to four arches). At this early stage, the construction supervisors were Francisco Sánchez de Aragón and Pedro y Vicente de San Martín. The inner facade of the plaza (called the "Palco del Príncipe" or "Prince's Box") was completed in 1765. This 'box' consists of two parts: the access gate through which the successful bullfighters exit, and the theater box itself, which is reserved for the exclusive use of the Spanish Royal Family. The topmost part is composed of four arches over which is built a half-orange vault, whose topmost portion is covered by white and blue tiles. The sculptural group that concludes the composition is the work of the Portuguese sculptor Cayetano de Acosta. The Palco was built for the Infante de España, Felipe de Borbón, son of Felipe V and Isabel de Farnesio.