Atlético Madrid was born on 26 April 1903 on the initiative of three Basque students living in the capital, who originally treated the club as a Madrid branch of Athletic Bilbao. It was not until 1921 that the Madrid side gained full independence, and their visual identity underwent a major evolution – from the initial blue-and-white kits to the iconic red-and-white stripes, introduced in January 1911. It was these colours, resembling the pattern of mattress covers at the time, that earned the team their legendary nickname Los Colchoneros (The Mattress Makers), eventually becoming a symbol of the working-class, proud and passionate part of Madrid.
For decades, the club built its power in the shadow of its wealthier neighbour, becoming synonymous with grit and resilience. The first major domestic successes came in the 1940s, with league titles in 1940 and 1941 under legendary goalkeeper-turned-coach Ricardo Zamora, followed by two more, in 1949–50 and 1950–51, under Helenio Herrera. The true golden era in the club's history, however, came in the 1960s and 1970s, driven on the pitch by Luis Aragonés – as captain and creative fulcrum of the attack, he helped win three Spanish championships (1966, 1970, 1973) and a Copa del Rey, and after retiring as a player in 1974 he went on to become the club's manager himself, later leading it to further honours, including the 1976–77 league title. In 1962, Atlético also secured its first European triumph, winning the European Cup Winners' Cup.
Although the turn of the century brought a painful moment for the club in the form of relegation from the league in 2000, Atlético Madrid managed to return in grand style, ushering in a modern era of success. Under the leadership of the charismatic Diego Simeone, who took charge in December 2011, the club permanently broke the duopoly of Real Madrid and Barcelona, winning two La Liga titles (2014 and 2021), twice triumphing in the Europa League (2012, 2018 – the club's third title in the competition had already come in 2010, before his arrival), and twice reaching the grand final of the Champions League, losing on both occasions to city rivals Real Madrid. This long and bumpy road shaped the club's characteristic, relentless ethos, which continues to define the strength of the Madrid team on the international stage – today played out at the Riyadh Air Metropolitano stadium.