Tucked away behind St George’s Chapel, Windsor, the Canons’ Cloister was built around 1350 on the site of former royal apartments for the chapel’s resident canons. That purpose has remained unchanged ever since, making the Canons’ Cloister unique as the earliest surviving collegiate range in Britain still remaining in its original use. It is also of huge significance as one of the earliest surviving parts of Windsor Castle. We have recently completed a two year programme of external and internal refurbishment of the Canons’ Cloister. Externally our work has included replacing degraded copper roofing with new lead work, repairs to chimneys, stonework and timber, and work to address damage caused by earlier phases of inappropriate (although well-meaning) repairs. Inside, we have brought the Canons’ accommodation up to modern standards while conserving not only the surviving fourteenth century structure but also later nineteenth century interventions. Inevitably with a building of this age, we have had to address serious structural issues and decay. As the buildings are part of the Windsor Castle Scheduled Ancient Monument, all work was carefully considered and subject to a complex Consent regime. We worked alongside a highly talented team of craftspeople and conservators to protect features including original timbers and plasterwork, as well as important and rare medieval wall paintings. Our work has not only ensured the survival of these beautiful and important buildings for many years to come, but has also led to an improved knowledge and understanding of Windsor Castle and medieval architecture.