Celtic art is an ancient style which had its beginnings over two and a half thousand years ago in Central Europe. As the Roman Empire grew to dominate Europe and then much of Britain, Ireland became the last bastion of the early La Tene style of Celtic art; highly stylized designs which decorated helmets, swords and other objects. Invasions by the Vikings and Anglo-Saxons and the advent of Christianity influenced the art form, which combined the old with the new and adapted into the spirals, step patterns and ribbon interlace which is recognized as Celtic art today. Some wonderful examples of Celtic design can be found in the Book of Kells, the Lindisfarne Gospels and other illuminated manuscripts which were created by Irish and Northumbrian monks in the 7th to 9th centuries. .