Real Madrid Castilla (also known as Real Madrid B) is the reserve team of the famous Spanish club, currently competing in Primera Federación and playing its home games at the 6,000-seat Alfredo Di Stéfano Stadium. As a reserve team in Spain, it cannot play in the same division as its senior side, meaning it is ineligible for promotion to La Liga and cannot compete in the Copa del Rey. The club originated as AD Plus Ultra in 1948, becoming Real's official feeder club in 1952, and was renamed Castilla CF in 1972 after Plus Ultra folded. Castilla enjoyed a golden age in the early 1980s, reaching the 1980 Copa del Rey final (losing 6-1 to Real Madrid) and winning the Segunda División in 1984 under coach Amancio Amaro, featuring the famous La Quinta del Buitre quintet of Emilio Butragueño, Manolo Sanchís, Martín Vázquez, Míchel, and Miguel Pardeza. Renamed Real Madrid B in 1991, the team has been a legendary talent factory, producing stars like Raúl, Guti, and Iker Casillas, and even had singer Julio Iglesias as a goalkeeper in the early 1960s before an injury ended his career. Despite being relegated to lower divisions in 1997, it has continued to develop internationally acclaimed players, cementing its role as a crucial stepping stone for future Real Madrid legends.