The Leaning Tower expresses the joys and sorrows of its earlier 800 years and waits for a happy end to its old-age convalescence with quiet wisdom. A widow, whose name was Berta of Bernardo, living in the house of dell’Opera di Santa Maria, the 5th of January 1172 left in her will sixty “coins” to the “Opera Campanilis petrarum Sancte Marie”, to purchase some stones to build the Tower.
As far as the author is concerned there is much uncertainty, experts are still arguing:
Would the architect have been Bonanno, marvellous bronze foundryman, who afterwards made the first Cathedral’s doors?
Or Deotiusalvi, one of the greatest architects of the XII century, who founded the Battistero?
Perhaps the work of Gerardo, who had to cooperate more as a co-author and interpreter than a simple executor of the orders given by Deotiusalvi?
Or Guidolotto, Designer of Santa Maria Maggiore?
Or was master Guglielmo, of German nationality, perhaps the same one who, in about the year 1160, carried out the first pulpit of the Cathedral ?
Whoever has done it, the author was fantastic. The only certainty is its date of birth, 9th August 1173.
The plan of the bell tower exists and it’s an admirable one. Of course it isn’t a design on paper but documented in the Tower itself and in its measurements.
This is the way the construction of the Bell Tower began. When the construction reached about one and half meters up on the third floor, because of marshy and unstable soil, it leaned fearfully, so the work was suspended. The events which led to the lean of the Tower were not known. The evidence we have are very uncertain. Surely two phenomenon took place, which were the reasons for the inclination: the building subsided due to the excess weight on the soils and the soils themselves underwent differential settlement.
The restarting of the work took place in two phases, during which they tried to reduce the slope. It is not known which height was reached at the end of the first phase of the resumption, before the intervention of Giovanni di Simone.
The second phase of the thirteenth-century, started probably about the years 1272-1275 and perhaps consisted of the building of four “loggette” (stories). In the sixth “loggetta” some round arch windows for the bells were made.
The lean continued to concern the Opera dell’ Duomo, so on the 15th March 1298, the Institution gave Giovanni Pisano, Guido, the son of the dead master Giovanni di Simone and Orsello, the task of measuring the slope.
Vasari ascribes the construction of the belfry to Tommaso, who was the son of Andrea Pisano, and it is usually dated, in the last studies, to the year 1350.
The Bell Tower, because of its lean, which looks like it dares the laws of statics, is one of the most original works of art of the whole European Middle-Ages, and enjoys an enormous popularity.