Towers of Bologna

The Towers of Bologna are a group of medieval structures in Bologna, Italy. The towers are the famous tourist attractions in Bologna. The two most prominent ones, also called the Two Towers, are the landmark of the city. The number of towers in the city was very high on 12th and 13th century, probably up to 180. The reasons for the construction of so many towers are not clear. One hypothesis is that the richest families used them for offensive and defensive purposes during the period of the Investiture Controversy.

Besides the towers, one can still see some fortified gateways that correspond to the gates of the 12th-century city wall, which itself has been almost completely destroyed. During the 13th century, many towers were taken down or demolished, and others simply collapsed. Many towers have subsequently been utilized in one way or the other as prison, city tower, shop or residential building. The last demolitions took place during the 20th century. The Artenisi Tower and the Riccadonna Tower at the Mercato di mezzo were demolished in 1917.

Of the numerous towers only twenty can still be seen today. Among the remaining ones are the Azzoguidi Tower, also called Altabella with height of 61 m, the Prendiparte Tower, called Coronata with height of 60 m, the Scappi Tower with height of 39 m, Uguzzoni Tower with height of 32 m, Guidozagni Tower, Galluzzi Tower, and the famous Two Towers the Asinelli Tower with height of 97 m and the Garisenda Tower with height of 48 m.

Recently, the city architectural tradition of tower building has been given a new lease with the "towers" of the Trade show district by the Japanese architect Kenzo Tange. The construction of the towers was quite onerous, the usage of serfs notwithstanding. To build a typical tower with a height of 60 meters would have required between three and 10 years of work. Each tower had a square cross section with foundations between five and ten meters deep, reinforced by poles hammered into the ground and covered with pebble and lime. The towers base was made of big blocks of selenite stone. The remaining walls became successively thinner and lighter the higher the structure was raised.

The first historian to study the towers of Bologna in a systematic way was Count Giovanni Gozzadini, a senator of the Italian kingdom in the 19th century, who studied the city's history intensively, not least to raise the prestige of his home town in the context of the now united Italy. He based his analysis mostly on the civic archives of real estate deeds, attempting to arrive at a reliable number of towers on the basis of documented ownership changes. His approach resulted in the extraordinary number of 180 towers, an enormous amount considering the size and resources of medieval Bologna.

More recent studies pointed out that Gozzadinis methodology might have led to multiple counts of buildings that could have been referred to in legal documents by different names, depending on the name of the family who actually owned it at a given moment. More recent estimates reduced therefore the number to a total between 80 and 100, where not all towers existed at the same time.

The Two Towers, both of them leaning, are the symbol of the city. They are located at the intersection of the roads that lead to the five gates of the old ring wall. The taller one is called the Asinelli while the smaller but more leaning tower is called the Garisenda. Their names derive from the families which are traditionally credited for their construction between 1109 and 1119. The name of the Asinelli family, for example, is documented for the first time actually only in 1185, almost 70 years after the presumed construction of the tower which is attributed to them.

It is believed that the Asinelli Tower initially had a height of ca. 70 m and was raised only later to the current 97.2 m with an overhanging rock of 2.2 m. In the 14th century the city became its owner and used it as prison and small stronghold. During this period a wooden construction was added around the tower at a height of 30 m above ground, which was connected with an aerial footbridge destroyed on fire in 1398 to the Garisenda Tower. Severe damage was caused by lightning that often resulted in small fires and collapses, and only in 1824 was a lightning rod installed. The tower survived, however, at least two documented large fires first in 1185 were due to arson and the second one in 1398 has already been mentioned above.

The Asinelli Tower was used by the scientists Giovanni Battista Riccioli in 1640 and Giovanni Battista Guglielmini for experiments to study the motion of heavy bodies and the earth rotation. In World War II, between 1943 and 1945, it was used as a sight post. During bombing attacks, four volunteers took post at the top to direct rescue operations to places hit by allied bombs. Later, a RAI television relay was installed on top. The Garisenda Tower has today a height of 48 m with an overhang of 3.2 m.

Initially it was approximately 60 m high, but had to be lowered in the 14th century due to a yielding of the ground which left it slanting and dangerous. In the early 15th century, the tower was bought by the Arte dei Drappieri, which remained the sole owner until the Garisenda became municipal property at the end of the 19th century. It was cited several times by Dante in the Divine Comedy and the The Rime. The Two Towers have also been subject of a homonymous poem by Giosue Carducci as part of the Barbarian Odes.