 El Greco's preference for exceptionally tall and slender figures and elongated compositions, which served both his expressive purposes and aesthetic principles, led him to disregard the laws of nature and elongate his compositions to ever greater extents, particularly when they were destined for altarpieces.The anatomy of the human body becomes even more otherworldly in El Greco's mature works; for "The Virgin of the Immaculate Conception" El Greco asked to lengthen the altarpiece itself by another "because in this way the form will be perfect and not reduced, which is the worst thing that can happen to a figure".A significant innovation of El Greco's mature works is the interweaving between form and space; a reciprocal relationship is developed between the two which completely unifies the painting surface.