 Helen Gardner suggests that Michelangelo made the change to the hemispherical dome of lower profile in order to establish a balance between the dynamic vertical elements of the encircling giant order of pilasters and a more static and reposeful dome.Gardner also comments, "The sculpturing of architecture [by Michelangelo] ... here extends itself up from the ground through the attic stories and moves on into the drum and dome, the whole building being pulled together into a unity from base to summit.