Prehistoric Celtic art comes from much of Iron Age Europe and survives mainly in the form of high-status metalwork skillfully decorated with complex, elegant and mostly abstract designs, often using curving and spiral forms. There are human heads and some fully represented animals, but full-length human figures at any size are so rare that their absence may represent a religious taboo. As the Romans conquered Celtic territories, it almost entirely vanishes, but the style continued in limited use in the British Isles, and with the coming of Christianity revived there in the Insular style of the Early Middle Ages.