Every Day Is Special: August 7 – Renaissance Begins

August 7 – Renaissance Begins – in Architecture!

Posted on August 7, 2014

The ancient civilizations of Greece and Rome were times of great art, great science and mathematics, great learning. Many other times and places are known for their flowering of art, invention, and science—the Egyptian pharaonic age in Africa, the Mayan and Incan civilizations in Central and South America, the Islamic Golden Age in Arabia and surroundings, the Indian and Chinese civilizations in Asia—but much of Europe struggled through centuries of what some call the “Dark Ages.” More often called the Middle Ages or medieval times, there was more burning books and smiting than we might like, and a little less scientific collaboration and artistic sharing than we might desire.

Until the Renaissance!

The Renaissance – a cultural rebirth, a flowering of exploration, innovation, and discovery that started in Italy in the late 1300s – impacted philosophy, science, music, and of course art, including painting and sculpture.

And including architecture.

The construction of the dome of Santa Maria del Fiore, in Florence, Italy, which began on this date in 1420, is considered the beginning of the Renaissance in architecture.

Actually, by 1400, the cathedral had been under construction for a century and still lacked a dome. The design for the dome had been completed long before, and a scale model that was 15 feet high and 30 feet long (4.6 m by 9.2 m) had been standing in a side aisle and was considered almost sacred at that point. But the dome design was a tricky one – it was an octagonal dome that was higher and wider than any ever built before – but it had no external buttresses to keep in from spreading and falling under its own weight.

Why no buttresses?

Apparently, because buttresses were used by Italy's enemies to the north, they were considered ugly and undesirable.

Architect Brunelleschi was supposed to build the dome, even though the internal invention needed to prevent spreading without buttresses had yet to be invented! He looked to the Ancient Roman dome called the Pantheon for a solution to the problem of building the impossible dome. The dome of the Pantheon was a single shell of concrete; a wooden form held the dome aloft while the concrete set. But there was not enough wood in all of Tuscany to build all the scaffolding and a form big enough to create the dome designed for this cathedral.

So Brunelleschi innovated. He created four internal horizontal stone and iron chains that were rigid octagon shapes; they served as barrel hoops, of sorts. The largest chain was placed at the bottom and embedded within the inner dome, and the smallest was located at the top; the other two were spaced at equal intervals within the body of the dome. There are also vertical ribs set on the corners of the octagon, curving toward the center point; the visible ribs are supported by 16 concealed ribs. The ribs had slits to support beams, which in turn supported the platforms that workers stood on to complete the higher and higher portions of the dome.

Brunelleschi also used a herringbone brick pattern to transfer the weight of the freshly laid bricks to the nearest of those vertical ribs, while the mortar was drying.

There was also an outer dome that relied on its attachment to the inner dome at its base to counteract hoop stress. The hoops were nine masonry rings that can only be seen in the finished cathedral from the space between the two domes.

The dome is crowned with an octagonal lantern that features eight high-arched windows. The cone-shaped roof of the lantern was topped with a gilt copper ball and cross – but in 1600 the ball was struck by lightning and fell down. Two years later, an even larger ball was made to replace the top piece.

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