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"It was in Central France, and mainly along the Loire, that the systematic development of vaulted church architecture began. Naves covered with barrel-vaults, sometimes of pointed section, appear in a number of large churches built during the eleventh and twelfth centuries, with apsidal and transeptal chapels and aisles carried around the apse, as in Notre-Dame du Port at Clermont-Ferrand. The thrust of these ponderous vaults was clumsily resisted by half-barrel vaults over the side aisles, transmitting the strain to massive side-walls."

Section of Notre-Dame du Port

"It was in Central France, and mainly along the Loire, that the systematic development of vaulted church…