Legacy systems are often business critical and are associated with high maintenance costs. In this paper, we present an overview of a method, Renaissance, which aims to manage the process of regaining control over such systems. Renaissance supports system evolution by first recovering a stable basis using reengineering, and subsequently continuously improving the system by a stream of incremental changes. In both cases, the extent of evolution is determined by a phase which takes account of technical, business, and organisational factors. Renaissance defines a process framework, a predefined number of evolution strategies, an information repository, and a generic set of personnel responsibilities. The method can be tailored to the needs of particular projects and organisations, and it is not prescriptive of particular tools and techniques.