(ANSA) - Vatican City, November 18 - Pope Benedict XVI turned into an impromptu art history professor on Wednesday, lecturing faithful on the importance of Europe's Medieval Romanesque and Gothic cathedrals.

Addressing the crowd at his weekly general audience, the German pontiff likened the cathedrals to "stone Bibles" which through sculptures and paintings illustrating episodes from the Gospel offer Christians a "privileged route" to draw closer to God.

"Christianity gave life not only to masterpieces of theological literature. It also inspired some of the most exalted artistic creations of all civilisation: the cathedrals, which are the real glories of Medieval Christianity," Benedict said.

Benedict recalled that from the 9th to the 14th century, European nations, particularly France and Italy, vied with each other to create artistic and architectural masterpieces.

The cathedrals, he said, were titanic endeavours which were built thanks to the contributions of the faithful, technical advancements in architecture and the know-how of brilliant architects.

Favourable historical conditions, including greater political stability which led people to move to cities, created a need for the construction of churches big enough to hold large congregations.

Romanesque churches introduced the use of sculptures which, as well as seeking technical perfection, had an educational aim, he said.

Statues, paintings and magnificent portals - whose recurring theme was the representation of Christ as Judge, surrounded by the figures of the Apocalypse - struck the viewer and helped him understand that Jesus is "the door that leads to heaven",said the pope.

Gothic cathedrals of the twelfth and thirteenth centuries were characterised by ''their vertical thrust and luminosity'' which aimed to translate in architectural lines "the longing of the soul for God".

They are a synthesis of faith and art "harmoniously expressed through the universal and captivating language of beauty," Benedict told the 8,000 faithful gathered at the general audience.

Their stained-glass windows heaped ''a cascade of light upon the faithful, recounting the story of salvation''.

"The force of the Romanesque and the splendour of Gothic cathedrals remind us that the way of beauty, is a privileged and fascinating way to approach the Mystery of God'', Benedict said.

photo: Leon Cathedral, Spain.