The name is sometimes written Bugail, which in ordinary Welsh means a herdsman or shepherd. Nothing is known of this saint, and his name does not occur in any of the genealogies; but he is generally identified with S. Vigilius we presume the early fifth century martyr-bishop of Trent (Austria), whose festival is June 26. The identification, however, is highly improbable, for the Latin vigilia, treated in Welsh as a doublet, has yielded in the old Welsh period the form gwyl, and in the mediaeval period mywyl. He is the patron of Llanfigel in Anglesey, which is under Llanfachraeth. Maen Bigel is the name given to a rock standing in the sea in Holyhead Bay, and also to another in the Sound of Bardsey. The West Mouse, a little island off the north-west coast of Anglesey, is called in Welsh, Ynys Bigel. Browne Willis gives the patron of Llanfigel as S. Vigilius, with festival November 1st. There was formerly a church, somewhere in the neighbourhood of Merthyr Mawr in Glamorganshire, which is called in the Book of Llan Ddv Merthir Buceil. The Pembrokeshire parish-name Begelly seems to be a derivative from the name.