This document introduces Redundant Architecture as a fundamental modeling principle, independent of domain, technology, or scale. Contrary to conventional approaches that treat redundancy as an implementation strategy or a corrective response to failure, the framework proposed here positions redundancy at the modeling level, prior to structure, instantiation, and application. Redundant architecture is defined as a constructive form in which global identity, essential function, and intrinsic value remain invariant under local component failure. Failure is not treated as an exceptional event but as an expected internal state of any asset intended to exist in time. As a result, no single component carries irreducible responsibility for system identity or function. The framework is articulated through: a clear model → structure → instances hierarchy, a conceptual diagram illustrating invariance under failure, and a set of axioms formalizing redundancy as a condition of modeling completeness. Although its formulation may appear a priori, the principle is explicitly derived from accumulated experience of loss, destruction, and failure. Redundant architecture is therefore understood as the formalization of the negative: a model shaped by the recognition of finitude and fragility, rather than by optimization or efficiency. This work is intended as a foundational, domain-independent reference, applicable to any field in which assets must persist over time, and as a basis for future theoretical, technical, or applied developments.