Considerable uncertainty surrounds the medieval patron of the church and origin of the place-name Llanilid. It is possible that Ilid was not a personal name but a geographical feature of some kind, although a saint Ilith or Tylith is recorded with reference to the church in the twelfth and thirteenth centuries. Forms of Ilid are associated with the church and place-name from the sixteenth century, and the saint has been identified amongst the many daughters of Brychan, who was linked to the area in a thirteenth-century source.

in other twelfth- and thirteenth-century sources Julitta is also clearly named as the patron of the church. At other churches she is a joint patron with her son Curig, and Curig is recorded as joint patron of the church in a sixteenth-century source.

While Curig is not associated with the church in the earliest sources, some confusion between a presumably local figure and the international saint Julitta is evident from the earliest references. However, if a cult of Julitta was based here in the medieval period, it is still likely that Curig would have held a significant place in the devotion and imagery of the church. Browne Willis gives a date of 16 July for the feast day (and a dedication of St Julitt), which is the feast day that he gives for Curig at Capel Curig in North Wales.