Gils is a common Norwegian name, and no doubt contributed to the English Giles, French Gilles, and Spanish Gil, though all these look to the Greek hermit in France, Aigidios, as their patron.  In the North, Ægidius is rendered by Ilian, Yljan, Yrjan, Ørjan, but not by Giles: and it would seem as if Julius had been confounded with the name, as well as, perhaps, Giolla, a servant. (History of Christian Names, Yonge, 1884).