The Bishop's Palace at Lamphey was a residence of the bishops of St. David's established before the Norman invasion, and used until the Reformation. It is likely that the earliest buildings on site were constructed of timber, although the date of this phase remains unknown. The earliest surviving masonry elements, including the limestone rubble western Old Hall and undercroft, date to the early thirteenth century. The remainder of the buildings are largely the work of the late thirteenth - earlier fourteenth century, with later alterations. There are the remains of great halls and chapels raised over basements, two gatehouses and a large barn or granary. The distinctive arcading is similar to that found at St Davids Bishop's Palace (NPRN 21633) and Swansea Castle (NPRN 94515), and wall paintings are recorded within the palace. There are also extensive remains of a medieval ornamental landscape (see NPRN 407112).

The Palace changed hands at the reformation and continued as a noble house into the seventeenth century, declining thereafter. In the nineteenth century the site was laid out as a garden (see NPRN 265874) associated with the gleaming classical mansion constructed to the north-west (NPRN 22219).

Sources include:
Turner, Rick. 2000. Lamphey Bishop's Palace, Llawhaden Castle, Carswell Medieval House and Carew Cross: Cadw Guide (Revised Edition).
Richard Suggett, Painted Temples: Wallpaintings and Rood-screens in Welsh Churches, 1200–1800, (RCAHMW 2021), pp. 89, 90.

RCAHMW 2021