Giolla Brigde, or Bridget's disciple, is thought to have contributed the Scottish examples of Gilbert, which is incorrectly explained by some as Gelb-bert, or yellow bright; but it is clearly traceable to the old Frank Giselbert, which see...
... There were four saints so called, namely, an abbot of Fontenelle, a great friend of William the Conqueror, an Auvergnat knight in the second Crusade, the English founder of the order of Gilbertine monks, and a bishop of Caithness; and it has been a prevalent name in England, Scotland, and the Low Countries, with many contractions, especially in the latter... (History of Christian Names, Yonge, 1884).