The Tre'r Ceiri Conservation Project 1989-99: preservation and re-examination of an iconic hillfort

Tre'r Ceiri, on the Llwn Peninsula, Gwynedd, is one of the most complete hillforts in Britain. The Tre'r Ceiri Conservation Project (1989-99) undertook a decade-long programme to stabilise the eroding dry-stone ramparts and huts while recording the monument in detail. The conservation project was successful in its primary aim of halting the erosion. The work revealed important constructional details of both the huts and ramparts, allowing two principal phases of occupation to be proposed. The first phase comprised large roundhouses, probably dating from the Iron Age. The fort was probably abandoned during the Roman invasion and reoccupied around the mid-second century AD. In the second phase, many of the earlier roundhouses were subdivided, and further irregular huts were added, producing about 160, mostly small, dry-stone structures. The north-west entrance was modified, and an outer rampart was either constructed or modified, producing a monumental outer entrance. The reoccupation and changes in the Phase 2 occupation were probably in response to the waning power of Rome and the resurgence of native tribal and social groupings. The change from large Phase 1 Iron Age roundhouses to numerous small Phase 2 structures suggests a modification in the function of the hillfort after its reoccupation, possibly in response to increased threat and social change.