Lobed Domes
Similar domes to that just described at Avignon are quite common in Spain, where for that matter the lantern itself had a very remarkable development. Thus in the cathedral of Zamora (consecrated 1144) there is a dome with sixteen ribs. It is not of perfectly simple type, however, for the masonry between the ribs is curved slightly outward, giving it the form of a lobed dome.[323] The lobes are comparatively small, but otherwise not unlike such larger ones as those in SS. Sergius and Bacchus at Constantinople (cir. 527) and the Serapeum of the Villa Adriana at Tivoli (125-135). As far as construction is concerned this arrangement made it possible to lay up the masonry between the ribs with little or no centering, so that once the ribs were in place, the task of completing the dome was a comparatively simple one. Unlike the “Gothic dome” which is later discussed, the thrusts were not materially decreased by the lobed plan and in its essentials the dome thus formed was precisely like the simple type. From the point of view of appearance these Spanish lanterns are certainly very beautiful. Usually pierced with windows in twelve out of the sixteen bays, and sometimes, as at Salamanca, with a few windows in the lower of the two stages forming the drum, they admit a great quantity of light to the very heart of the church where its presence is most needed. Moreover, the spherical pendentives from which the lanterns rise are more pleasing than the squinches generally found in France.