Some say construction workers engineered the tilt to protest their measly compensation. Others assert it was a hunchback architect paying homage to his own lopsided body.
Whatever one believes, the Leaning Tower of Pisa has resisted gravity for so long that to reveal its true origins seems akin to blasphemy. Why rob tourists of something that gives them an excuse to wonder?
In his lively new book, "Tilt," Nicholas Shrady puts to rest of some of these entertaining but erroneous myths without ruining the tower's sense of mystery. As it turns out, the campanile's true history is just as fabulous as the tall tales that cling to its marble arches. It is a story full of architectural genius and sedentary slippage in which popes, poets, and warriors all had their shot to explain Pisa's phenomenon, and failed.
To understand the campanile, Shrady argues, you need to know a bit about Pisa. And so "Tilt" takes readers on a breezy tour of Pisan history, beginning in the 8th century, when the city was a shipbuilding center known for its "Cathargian spirit." Originally, Pisans were not raiders but traders. It was in defense of their commerce that they battled with - and eventually defeated - the Saracens, a tribe from Syria and Jordan that had been encroaching upon their territory.
In the two centuries that followed, Pisa, enriched by free travel to the Middle East, the Crusades, and the booty its denizens claimed in their sea victories, began a building spree to celebrate its newfound power. The tower of Pisa came toward the end of this period, when Pisan architects had raced to the forefront of mixing Arabic and classical design motifs to create what has since been known as Romanesque style.
Reading about how the tower was built makes today's modern construction feats seem paltry. In order to transport the marble from a nearby quarry to Pisa, a canal was dug and the "best marble of Italy" floated down to the construction site in astounding quantities. "The masons needed enough stone to shape 32,240 blocks," writes Shrady, "15 half columns for the ground story; 180 columns for the arcades; 12 columns for the belfry, column bases and capitals, hundreds of arches, vaults, corbels, and jambs; and, finally, 293 steps for the interior stairwell."
What is amazing about the tower is not so much that it stands today, but that it was ever completed at all. Work began in 1174, but stopped in 1178 when the structure was only half built, probably because of "a sudden shift in terrain."
Work didn't resume for another 98 years, by which point Romanesque style was out and Gothic was in. And the tower didn't receive its lovely belfry until 1384, by which point Pisa's fortunes had reversed. In the years that followed, the tower became a symbol for man's hubris, rather than Pisan success. Romantic poets like Shelley and Byron, who lived in Pisa, adored its sense of ruin. The tilt became a tourist attraction - in the beginning, mostly for architects.
Like a man slowly balding, the campanile's tilt progressed at such a slow pace - a few millimeters a year - it wasn't until things had gotten quite bad that drastic steps were considered. Over nine centuries of its lifetime, 17 different commissions pondered the tower's dilemma, with one notable failure coming during Mussolini's reign. Ninety tons of marble were pumped into the structure's foundation, causing it to sway dangerously.
The 17th commission, however, achieved success in 2000. A team of specialists, led by an English soil expert removed 60 tons of dirt from beneath the campanile's north side, and the gigantic structure moved 40.6 centimeters back toward perpendicular. After being closed for nearly 10 years, this lucrative tourist attraction has opened again.
In one fell suck of soil, centuries of tilting was reversed and the power of the tower preserved. Mankind, whose folly the tower now celebrates and flaunts, had, alas, fixed what had been wrought. At least - Shrady says with a wink and a nod - for a little while.
• John Freeman is a freelance critic in New York.