This paper tells the story of the AEGIS Weapon System product line and how it evolved from a series of standalone software programs with no sharing into a true systems and software product line. The paper focuses on the strong internal and external governance of the product line. The need for strong governance is brought about by the strong role that the AEGIS customer community plays in oversight of design, development, and procurement. The paper recounts the product line's beginnings, and describes how the product line is operated today. Organizational issues, measurement issues, and governance issues are covered, along with a summary of important lessons learned about operating a product line in an environment of strong competing interests.