An inscribed altar stone found at Chapel Ia, Troon (now set up as the Lady Chapel altar in the parish church), and dated to the 10th or 11th centuries, attests to the existence of a settlement then. It is inscribed 'Leuiut iusit hec altare pro anima sua'. The chapel of St Ia was recorded in 1429 and a holy well was nearby. The site was called Fenton-ear (i.e. the well of Ia). The stone is very similar to one now used as the mensa of the Lady Chapel altar at Treslothan Parish Church, formerly used from c.1841 to 1955 as the base for a sundial in the grounds of Pendarves House.