Since the late 1980s, software architecture has emerged as the principled understanding of the large-scale structures of software systems. From its roots in qualitative descriptions of empirically observed useful system organizations, software architecture has matured to encompass a broad set of notations, tools, and analysis techniques. Whereas initially the research area interpreted software practice, it now offers concrete guidance for complex software design and development. It has made the transition from basic research to an essential element of software system design and construction. This retrospective examines software architecture's growth in the context of a technology maturation model, matching its significant accomplishments to the model's stages to gain perspective on where the field stands today. This trajectory has taken architecture to its golden age.