The series was "lost" after a fire at the BRB Internacional, S.A. studios destroyed the masters of its opening sequence. It was resurrected in 2005, for its DVD release, complete with new opening and closing songs and credits.
The first co-production done by the Spanish animation company BRB Internacional, S.A. and Japan's Nippon Animation, Ltd.
The series featured historic characters that already appeared on the medieval poem "El Poema de Mio Cid", namely Ruy's parents, his cousin Alvar, Ximena, Count Lozano, King Ferdinand I and his sons Alfonso, Sancho and Urraca, among others.