The amalagamation of St. Mary's College and St. Joseph's High School, Lismore was a process that began in 1965 when a decision was made to combine Senior classes for the first Higher School Certificate curriculum. There was no thought of amalgamation in 1965 but the decision made then lead to the developments of 1977. Increasing enrolments and the need for a building programme set the scene for a merger of Junior classes and the introduction of coeducation throughout the schools. This process extended from 1977 to 1981. It was a period of conflict and resistance to change but it laid the foundation for the complete amalgamation of the schools to form Trinity Catholic College in 1985. The amalgamation process provides a study of decision-making in a Catholic school context. Changes in the Church, Catholic schools and Religious Orders are reflected in the changes in the way that decisions were made at the three key-points in the story. The study draws attention to the fact that in amalgamations of schools much of the planning is done in terms of the present schools rather than for the new school which is always twice as large and much more complex. The non-educational aspects of amalgamation are also considered because they are a time-consuming but important part of the planning. This study shows the importance of rituals in laying the old schools to rest so that the new school may come into being. A visible indication that things are different is essential when the students, staff and buildings remain as they had been. Since amalgamations are becoming more common as student numbers decline some lessons learned over the past twenty years are recorded so that others may benefit from them.