Digital sovereignty has emerged as a central concern for mod- ern software-intensive systems, driven by the dominance of non- sovereign cloud infrastructures, the rapid adoption of Generative AI, and increasingly stringent regulatory requirements. While ex- isting initiatives address governance, compliance, and security in isolation, they provide limited guidance on how sovereignty can be operationalized at the architectural level. In this paper, we ar- gue that sovereignty must be treated as a first-class architectural property rather than a purely regulatory objective. We introduce a Sovereign Reference Architecture that integrates self-sovereign identity, blockchain-based trust and auditability, sovereign data governance, and Generative AI deployed under explicit architec- tural control. The architecture explicitly captures the dual role of Generative AI as both a source of governance risk and an enabler of compliance, accountability, and continuous assurance when prop- erly constrained. By framing sovereignty as an architectural quality attribute, our work bridges regulatory intent and concrete system design, offering a coherent foundation for building auditable, evolv- able, and jurisdiction-aware AI-enabled systems. The proposed ref- erence architecture provides a principled starting point for future research and practice at the intersection of software architecture, Generative AI, and digital sovereignty.