In the last fifteen years new documentary research on the buildings of the earliest stage of Carlos Arniches and Martín Domínguez – members of the Madrilean “Generation of 1925” key to the introduction and development of the Modern Movement in Spain –, reveals the convenience of a revision of the historic tale as related to the authorship of several of the buildings by these architects, including partnered and sole works. The contradictions and few coincidences between primary and secondary sources, solved in great extent by a new documentary and archival research, fret the role played by those sources as far as the historic tale of the facts is concerned. Previous research on those two architects revealed the importance of architectural authorship when it came to analyse works of architecture, suggesting the need to further explore that line of research – which finally almost included their whole production. Despite those architects having worked occasionally as partners before 1936, evidences and archival documents prove that only a few works were partnered – of which some were even misattributed. The context – one of the keys to understanding documentary and archival material – and an exhaustive evaluation process – including historic and cultural points of view – reveal the true authroship, and lead to settling events as they happened, thus preserving their historic testimony and values.