Perhaps it’s no surprise that the hospitable Irish took in a “foreigner,” a Welshman named Patrick, and made him their own patron saint! And Saint Patrick’s Day, that exuberant day of merriment, comes around again this month, on the 17th of March. The Irish also gave the world Halloween, another day of revelry, but in their defense, they’ve made considerable contributions in most areas of the arts: from literature, to music and fine art. Ireland boasts painters of note going back through the centuries, but few that can still draw a crowd like the anonymous artisans—devotees of the Christian faith and of St. Patrick himself—who illustrated the Book of Kells. At its core the Book of Kells is simply a Christian Bible containing the four Gospels of the New Testament. At just 10 by 13 inches, it dates from around A.D. 800, and along with delicate, hand-painted Latin calligraphy, it …