Over seventeen years (1990-2007) and three conservation campaigns, the ACL has provided research, documentation, and treatment for the 155 existing identified gravestones at Trinity Cathedral. Phase I (1990-91) included the compilation of relevant historical information, preparation of condition reports for the markers, and execution of pilot conservation treatments on eight representative markers. In 1999 Phase II continued the project by expanding the research and treatment program - including various chemical and mechanical treatments to the stones as well as temporary protective burial under gravel and geotextile and clover plantings to mitigate on-site drainage problems. The current Phase III began in November of 2006 focuses on the conservation of the remaining monuments and the redesign of the churchyard landscape. The program extends the life of the site markers by reducing the rate of decay while respecting the original fabric through minimal material intervention. This phase of the project includes assessing the earlier prototypical treatments, testing to develop new preservation treatments, implementing the revised conservation interventions, and establishing new recommendations for continued site preservation. Andropogon, a Philadelphia-based landscape architecture firm, developed a contemporary redesign of the 250-year-old cemetery providing better access and visual continuity to the site while respecting the integrity of the burial ground as a historic and sacred landscape.