Contracted from MacGiolla or MacGuilly Chreest, 'the Son of Christ’s servant', or possibly from Mael Chreest, 'the Tonsured Servant of Christ'.

'Giolla', says O'Donovan, 'especially among the ancients, signified a youth, but now generally a servant, and hence it happened that families who were devoted to certain saints, took care to call their sons after them, prefixing the word Giolla, intimating that they were to be the servants or devotees of those saint'. And he continues: 'Shortly after the intro­duction of Christianity, we meet many names of men formed by prefixing the word Giolla to the names of the celebrated saints of the first age of the Irish Churchy as Giolla-Ailbhe, Giolla- Phatraig, Giolla-Chiasain. . . . And it will be found that there were very few saints of celebrity, from whose names those of men were not formed by the prefixing of Giolla. . . . This word was not only prefixed to the names of saints, but also to the name of God, Christ, the Trinity, the Virgin Mary, . . . .Professor Zimmer, in a review of this book, absolutely traverses the statement in italics, and he denies that giolla is a genuine Irish word, and he remarks that anyone can see that in the first century after the introduction of Christianity the names formed from the names of celebrated saints of the Irish Church are found in Ireland only with mael (calvus—i.e., tonsured or bald). He then points out that in O’Donovan’s Index to the Annals of the Four Masters there are, between the sixth and twelfth centuries, 354 persons men­tioned, whose names are formed with mael or maol, and in fairly equal proportions for each century, whereas, in the same Index, 56 persons only are mentioned whose names are found with giolla or gilla, and of these the earliest occurs in 982, while 49 out of the 56 names are of the eleventh and twelfth centuries. With these statements he couples the fact that the conversion of the Vikings in Dublin, Limerick, and Waterford began in 943, and he comes to the conclusion that persons met with from the end of the eighth to the end of the twelfth century having names compounded with giolla are, for the most part, Vikings converted to Christianity and to Irish citizenship. Considering the question also from a linguistic point of view, he decides that the word gilla is not of Gaelic or even of Celtic origin, and that the British name Gildas, which has been supposed to be cognate to gilla, is really a loan word from the Norse- i.e., in the same way as the Irish iarla is the Norse iarl-r, so gilla, ‘stout youth', is equivalent to the Norse gild-r, ‘strong, brawny'.

While allowing that Professor Zimmer's argument is a strong one, we cannot admit that it is absolutely convincing. We would point out that Gildas occurs in Bede, who wrote before the arrival of the Northmen, and that in the story of Kulhwch Gildas appears as Gilla; also that Professor Zimmer has only succeeded in producing an adjective—gild-r—not having been able to show a trace of any change of this adjective into a Celtic noun with the sense of 'a strong fellow', or 'a stalwart young man'. On the whole, then, we must consider his theory as 'not proven'. Its effect is to place Lewin, Fayle, Sayle, KilleY, Gill, and a number of obsolete names, under 'names of Scandinavian origin' while Mylchreest, Mylvorrey, Mylecharaine, Bridson, and possibly Mylrea, which can be derived either from MacGilla or Mael, might be either Celtic or Scandinavian. But we should mention that, in the Isle of Man, the earlier form, which, however, cannot be traced, in the absence of records, before the fifteenth century, is invariably MacGil or MacGille, The process of change is probably as follows: MacGille or Macguilley becomes Mac- cuilley or Magguiltey; the a of mac being unaccented dis­appears with the consonants, leaving Muilley, which then becomes My ley, pronounced Mully. Mylchreest, as the name is now generally spelled, is invariably pronounced Mul- leychreest or Molleychreest by old Manx people, which perhaps also points to the derivation from Mael as being the more probable. This name and all those commencing with 'Myle' are purely Manx.

‘Gillacrist, son of Niall . . . slain', a.d. 1014.