Why does a system exhibit the architecture that it does? What influences affected the architectural decisions made by its designer(s)? We hypothesize that these influences flow from the system's requirements, the organization's culture and goals, and the designers' experience and background. We posit that the influences are at least partially enumerable, as are the architectural decisions that they precipitate. This paper discusses the approach taken in a pilot study to uncover the correlation, if any, between architectural influences and architectural decisions in large-scale, software-intensive development projects. We discuss the information extracted in the context of a set of architectural case studies of systems including air traffic control, shipboard fire control, military command centers, machine controllers, database management systems, and flight simulators.