This work presents a theoretical and methodological inquiry into the rewards of reconsidering what is commonly understood to be irrelevant in discussions in architecture, in this case a significant protagonist who has remained invisible until now, namely Lina Loos, Adolf Loos's first wife. Her own writing, especially in an article she authors and publishes in 1904, 'Vandals', shows an early concern, exemplified by references to architecture, for a significant Loosian topic: the material manifestation of modernity. Considering this, the text searches for reasons for her absence from the discussion in architecture while arguing for Lina Loos's significance in two of Loos's projects, 'My wife's bedroom' and 'Ornament and Crime'. The text starts by debating Lina Loos-s overall absence from academic discussions until the end of the twentieth century and her still persisting absence from architectural discussions in particular. Given that her writing shows a good grasp on a variety of fin-de-siècle topics, among them the material consequences of modernity, the text continues by searching for possible reasons for her continuing irrelevance within the boundaries of the architectural discussion. In this context, the writing of history, changing schools of thought and authorities are discussed as they provide and manipulate the available and relevant topics and materials, which form the basis for the architectural discussion and determine its outcome. In Lina's case, her status as a woman without professional affiliation contributes to a great degree to her alleged irrelevance in architecture. When she is considered at all in architectural discussions until now, Lina Loos appears as Adolf Loos's muse for the bedroom project in their marital apartment. This concept is debated as hindering the scholarly discussion in architecture from moving beyond an understanding of Lina as the provider of creative inspiration for someone else, onto an understanding of her as an active and significant protagonist. Freeing Lina of her problematic status, both as a woman without professional affiliation and muse, and following cluesiv provided by her biographers and other disciplines, the final discussion entails discussing Lina Loos's role as a significant protagonist in architecture. It is argued that only with her influence as a client, Adolf Loos is able to conceive of the unique aesthetic of 'My wife's bedroom' and, most importantly, to articulate his powerful ideas on ornament, which culminate in his manifesto 'Ornament and Crime'. 'Vandals' and 'Ornament and Crime' are presented as a dialogue between authors, the former enriching Adolf Loos's thoughts by architectural examples. Lina Loos and her piece 'Vandals' are a necessary and significant part of the discussion surrounding 'Ornament and Crime'. What makes Lina Loos especially central is that, beyond her contribution to the outcome of an architectural project as a client, she is a significant protagonist in architectural theory.