Soon after his arrival at Sigeberht's court, Felix established a church at Dommoc, his episcopal see, which is widely taken to mean Dunwich, on the Suffolk coast. Dunwich has since been almost totally destroyed by the effects of coastal erosion. Other historians have suggested as an alternative site for Felix's see the coastal Walton, Suffolk near Felixstowe, where there was once a Roman fort, Walton Castle, since washed away by the sea. A church and priory were dedicated to him there by Roger Bigod in 1105.