According to Giorgio Vasari (1511-1574), the famous biographer of Renaissance painters, sculptors and architects, Luca della Robbia’s technique was so revolutionary that he’d be praised for it for many centuries to come. He explained how it was not such a hard work to make a clay sculpture and the only reason why clay had not been used much so far was that it could not be preserved over time. Luca, after many experiments, managed to invent a special mixture of minerals. This glaze, used to coat the sculptures before the firing in a suitable kiln, would make them almost eternal.
