The Leaning
Tower of Pisa Italian: Torre pendente di Pisa or simply the Tower of Pisa Torre
di Pisa is the campanile, or freestanding bell tower, of the cathedral of the
Italian city of Pisa, known worldwide for its unintended tilt to one side. It
is situated behind the Cathedral and is the third oldest structure in Pisa's
Cathedral Square Piazza del Duomo after the Cathedral and the Baptistry. The tower's
tilt began during construction, caused by an inadequate foundation on ground
too soft on one side to properly support the structure's weight. The tilt
increased in the decades before the structure was completed, and gradually
increased until the structure was stabilized and the tilt partially corrected
by efforts in the late 20th and early 21st centuries.
The height
of the tower is 55.86 metres 183.27 feet from the ground on the low side and
56.67 metres 185.93 feeton the high side. The width of the walls at the base is
2.44 m 8 ft 0.06 in. Its weight is estimated at 14,500 metric tons 16,000 short
tons. The tower has 296 or 294 steps; the seventh floor has two fewer steps on
the north-facing staircase. Prior to restoration work performed between 1990 and
2001, the tower leaned at an angle of 5.5 degrees, but the tower now leans at
about 3.99 degrees. This means that the top of the tower is displaced
horizontally 3.9 metres 12 ft 10 in from where it would be if the structure
were perfectly vertical.
Architect
There has
been controversy about the real identity of the architect of the Leaning Tower
of Pisa. For many years, the design was attributed to Guglielmo and Bonanno
Pisano, a well-known 12th-century resident artist of Pisa, famous for his
bronze casting, particularly in the Pisa Duomo. Bonanno Pisano left Pisa in
1185 for Monreale, Sicily, only to come back and die in his home town. A piece
of cast with his name was discovered at the foot of the tower in 1820, but this
may be related to the bronze door in the façade of the cathedral that was
destroyed in 1595. However, recent studies seem to indicate Diotisalvi as the
original architect due to the time of construction and affinity with other
Diotisalvi works, notably the bell tower of San Nicola and the Baptistery, both
in Pisa. However, he usually signed his works and there is no signature by him
in the bell tower which leads to further speculation.
Construction
Construction
of the tower occurred in three stages across 199 years. Work on the ground
floor of the white marble campanile began on August 14, 1173, during a period
of military success and prosperity. This ground floor is a blind arcade
articulated by engaged columns with classical Corinthian capitals.
The tower
began to sink after construction had progressed to the second floor in 1178.
This was due to a mere three-metre foundation, set in weak, unstable subsoil, a
design that was flawed from the beginning. Construction was subsequently halted
for almost a century, because the Republic of Pisa was almost continually
engaged in battles with Genoa, Lucca, and Florence. This allowed time for the
underlying soil to settle. Otherwise, the tower would almost certainly have
toppled.[citation needed] In 1198 clocks were temporarily installed on the
third floor of the unfinished construction.
In 1272
construction resumed under Giovanni di Simone, architect of the Camposanto. In
an effort to compensate for the tilt, the engineers built upper floors with one
side taller than the other. Because of this, the tower is actually curved.
Construction was halted again in 1284, when the Pisans were defeated by the
Genoans in the Battle of Meloria.
The seventh
floor was completed in 1319. It was built by Tommaso di Andrea Pisano, who
succeeded in harmonizing the Gothic elements of the bell-chamber with the
Romanesque style of the tower. There are seven bells, one for each note of the
musical major scale. The largest one was installed in 1655. The bell-chamber
was finally added in 1372.
After a
phase 1990–2001 of structural strengthening, the tower is currently undergoing
gradual surface restoration, in order to repair visible damage, mostly
corrosion and blackening. These are particularly pronounced due to the tower's
age and its exposure to wind and rain.
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