from one another by ribs which conceal the groins, or the intersections of the panels. Rib vaults are, like groin vaults, formed from two or three intersecting barrel vaults; the ribs conceal the junction of the vaults.

The first rib vaults were built by the ancient Romans in the 2nd century AD. In the medieval period the earliest surviving example in Islamic architecture is at the Mosque-Cathedral of Córdoba