At that time, Athletic de Madrid was not one of the greats in Spain, having only accumulated a handful of titles in their first decades of history – three
Campeonato Regional Centro (1921, 1925 and 1928) and two
Copa del Rey runners-up medals (
1921 and
1926) – and although it was one of the ten teams that founded
La Liga in 1928, Athletic came last in the standings in just the league's
second edition in 1930 and fell to the
Second Division. The club did not return to the top flight until 1935, just to descend again the following year, in 1936, shortly before the league was stopped due to the outbreak of the Civil War. By the end of the war, Athletic found itself in a difficult situation because they were lacking a suitable
playing field as the
Metropolitano had been completely destroyed by the war, lacking players because its squad had been decimated (including the club's star,
Monchín Triana, who was shot down), and it accumulated an economic deficit that envisaged a dark future in its sporting and financial horizon. Moreover, Athletic was facing the possibility of being relegated to the Second Division due to having been penultimate in the
1935–36 La Liga, the last before the War. However, Athletic managed to find a lifeline in the form of a military group, Club Aviación Nacional, who will save them from an almost certain disappearance. The directors of Athletic de Madrid, Cesáreo Galindez and Juan Tourón proposed to Captain Bosmediano and Lieutenant Salamanca, an agreement that could benefit everyone. Aviación Nacional had previously tried to merge with Real Madrid, but the conditions that the military club had proposed did not convince the Whites. Aviación required to impose its name, its shield, the colors of its uniform, and 50% of the directors and the president, and those demands did not convince Athletic either, since they did not want to lose their hallmarks. The negotiations were not easy, since
Nacional de Madrid was also interested in merging with Aviación Nacional. Fearing this possibility, Athletic succumb to the conditions and a pre-agreement was reached in September 1939, and so, on 4 October, the representatives of both sides signed the absorption agreements and appoint the first Board of Directors with Commander
Francisco Vives Camino as president of the now
Athletic-Aviation Club. Even though this agreement is sometimes referred to as a "merge", it was not legally one (which explains why the 1939 Aragon Regional Championship, which the aviator club won in 1939, is not counted among the Atlético's titles), but rather just a change of name of the Madrid club under certain conditions. Either way, thanks to this agreement, the future Atlético went from ruined by the war to saved by Aviación. ==National dominance==