In the Oratory of the Crib ( Oratorio del Presepio ) are the moving 13th-century sculptures of Joseph , the Three Kings , the ox , and the ass , by Arnolfo di Cambio ( Mary and the child Jesus are 16th-century additions ) .
Joseph , the Three Kings , the ox , and the ass appear in sculpture form in di Cambio 's Oratory of the Crib .