Why is Business Architecture the first architecture activity undertaken?

Business Architecture is recognized as the first architecture activity undertaken primarily because it serves as a foundational prerequisite for other architecture domains within the TOGAF framework. This architecture domain focuses on understanding and articulating the business strategy, governance, organization, and key business processes of an enterprise. By establishing a clear understanding of these factors, Business Architecture provides the necessary context for other architectures, such as Data, Application, and Technology architectures, to be effectively developed and aligned.

When Business Architecture is clearly defined, it enables architects to ensure that subsequent architectural efforts are tailored to meet the specific business objectives and needs. This alignment is critical in ensuring that the overall enterprise architecture remains relevant and effectively supports business goals, leading to coherent and strategic architectural design in the areas that follow. Hence, it is the cornerstone upon which the rest of the architecture is built.