Sir John Stanley upheld the theory that a Roman Temple originally existed within the present churchyard walls, and that on the departure of the Romans it was occupied or used as a church. Whether this were so or not, it is clear that in the days of Caswallan Llaw Hir, Son of Cynetha, there was a burial-place within the fort at Holyhead, inside the present walls encircling the churchyard. Here Caswallan routed and slew with his own hand Sirigi, the Irish giant, who, with a following of Irish Picts, had a short time before forced a landing and had built a place or town called first Llan-y-Gwyddel, then Caer Gybi, and now in English, Holyhead. Within the enclosure where Sirigi was slain stood a chapel, on the south side of the church, some remains of which (conspicuous among them a Gothic arch) are still extant, and here, it is affirmed, the Irish giant was buried. This was called Eglwys-y-Bedd, the Church of the Grave, and Capel Llan-y-Gwyddel, or the Chapel of the Irishman. It appears, from leases of the collegiate church, that this chapel was endowed with distinct revenues in the reign of Edward III. Some of the ruins were removed in the last century to render the entrance to the present church more convenient, and in digging, a stone coffin was found under an arch, on the north side of the chancel, containing bones of a large size, and this probably was the shrine of Sirigi, who was canonized by the Irish. According to an old chronicle, they carried off his body and deposited it in their cathedral in Dublin; but the finding of the coffin with the gigantic bones seems to render this part of the story improbable. Caswallon had apparently a very fierce conflict with the Irish Picts before he gained his victory, and moreover could not have had much confidence in his own men, for we read that he tied them together in couples, with horse fetters, to prevent their breaking their ranks when fighting with Sirigi. This prince settled himself after his victories at Llaneillan, and was submitted to as Chief or King of Anglesey. There are remains of a strongly fortified camp near the summit of Holyhead mountain, still called Mur Caswallon or Caer-y-Twr. Caswallon’s son was the famous Maelgwyn Gwynedd, the hero of many battles and the terror of the Saxons. He erected the See of Bangor about the year 550, where, a short time before, Daniel, the son of Dionothus, Abbot of Bangor-is-Coed, had built a college for North Wales clergy. Maelgwyn Gwynydd founded the college and the three canonries of Bangor, Penmon and Caer Gybi. Others say that Llywarch-ap-Bran founded the Prebendaries. His arms, the three crows, are in the porch of St. Cybi’s Church, at Holyhead. [Picture: South Doorway, Holyhead Church, Anglesey (1862)]