dling against it
both on the outside and the inside, that it seems to have been actually
invisible. So much so that contemporary chroniclers spoke of Pisa as
without walls, and attributed her safety to the valor of her citizens
and the multitude of her towers. The ancient wall was evidently so
hidden and decayed that Pisa must be regarded as a defenseless city in
the twelfth century. It is curious that her citizens should have
neglected their own safety at a time when they were masters of
fortification and defense; when their fame in these arts had reached as
far as Egypt and Syria, and when the Milanese came to them to beg for
engineers....

The external appearance of an Italian city in the twelfth century was so
unlike anything we are accustomed to in modern times that a strong
effort of the imagination is needed to conceive it. Seen from a distance
the walls enclosed, not houses, but a forest of tall square shafts,
rising into the sky like the crowded chimney stacks in a manufacturing
town but far more thickly set together. The city appeared, to use a
graphic contemporary metaphor, like a sheaf of corn bound together by
its walls.

[Illustration: PANEL IN THE CATHEDRAL, SHOWING PART OF THE MEDIEVAL WALL
AND TOWERS OF PISA]

San Gimignano, tho most of its towers have perished long ago, helps us
to imagine faintly what Italian towns were like in the days of Frederick
Barbarossa or his grandson Frederick II. For most of the houses were
actually towers, long rectangular columns, vying with each other in
height and crowded close together on either side of the narrow, airless,
darkened streets. Sometimes they were connected with one another by
wooden bridges, and all were furnished with wooden balconies used in
defensive and offensive warfare with their neighbors.

Cities full of towers were common all over southern France and central
Italy, but Tuscany had more than any other state, and those of Pisa were
the most famous of all. The habit of building and dwelling in towers
rather than in houses may have arisen from the difficulty of expanding
laterally within an enclosed city; but a stronger reason may be found in
the dangers and uncertainty of life in a period when a man might be
attacked at any moment by his fellow-citizen, as well as by the enemy of
the state. It was a distinct military advantage to overlook one's
neighbor, who might be an enemy; and towers rose higher and higher. The
spirit of emulation entered,