The Ottomans mastered the technique of building vast inner spaces confined by seemingly weightless yet massive domes, and achieving perfect harmony between inner and outer spaces, as well as light and shadow. Islamic religious architecture which until then consisted of simple buildings with extensive decorations, was transformed by the Ottomans through a dynamic architectural vocabulary of vaults, domes, semidomes and columns. The mosque was transformed from being a cramped and dark chamber with arabesque-covered walls into a sanctuary of esthetic and technical balance, refined elegance and a hint of heavenly transcendence.