Topic summary
Vaulting
Extracted from the Wikipedia article Vault (architecture).
Vaulting and faux-vaulting in the Renaissance and after
Whereas Roman vaults, like that of the Pantheon, and Byzantine vaults, like that at Hagia Sophia, were not protected from above (i.e. the vault from the inside was the same that one saw from the outside), the European architects of the Middle Ages protected their vaults with wooden roofs. In other words, one will not see a Gothic vault from the outside. The reasons for this development are hypothetical, but the fact that the roofed basilica form preceded the era when vaults begin to be made is certainly to be taken into consideration. In other words, the traditional image of a roof took precedence over the vault.