Life in Venice called forth one of the earliest and most glorious examples in modern times of a town square enclosed by loggias. This was probably because the water-locked community had to devise ways to live compactly and contentedly together. The story of its wonderful walkways begins in the late 12th century, when, under Doge Sebastiano Ziani, Venetian political and commercial authority grew. At that time, the size of the Doge's Palace with its halls of government, and San Marco, the Doge's chapel, kept pace, too.
Ziani removed an orchard from the west half of the space we now know as Piazza San Marco. He covered over a canal (the Rio Batario) that divided the area and bordered the piazza with arcaded dwellings, establishing a model for centuries to come.
This ``square'' edged with loggias, apparently unique in 13th-century Italy, reverberated with colorfully clothed traders and crusaders arriving with exotic beasts and treasures from the Orient.
The Venetians themselves must have loved Ziani's long porticoes, vivacious with stilted horseshoe-shaped arches. These were in the spirit of the Islamic East, which, with Byzantine Greece, was at the heart of the Venetians' trading empire.
Through these long loggias, the artisans, citizens, noble Venetians, or travelers could circle around the whole civic courtyard.
Passing by simple craftsmen's shops, they would move through the covered ``porch'' of the Doge's chapel, San Marco, cozily contained beyond the buffetings of squall, snowstorm, or baking sun.
The covered walkways parallel the public processions that once gave shape to the open space in the center. Venice was a society on foot. There, life in the open air could be as civilized as indoors, or as in the porticoes sharing benefits of indoors and out.
When a fire damaged several houses behind the northern range of arcades in 1512, the Procurators (lifetime appointees in charge of the buildings of the Piazza San Marco and second in power only to the Doge) ``restored'' the whole northern portico, adding a story to the houses, updating the forms.
Since the city was almost bankrupt from the War of the League of Cambrai, this rebuilding signaled to Venice's enemies that it intended to triumph in the struggle it appeared to be losing.
Venice did win, and two decades later stood ready to complete the urban center.
In 1468, the republic had inherited one of the world's finest collections of Greek manuscripts, owned and cataloged by Cardinal Bessarion, Patriarch of Constantinople. He had transported the codices by muleback from Florence the year before to avoid their appropriation by the Medici.
The first endeavor in completing the urban center concerned this collection. Jacopo Sansovino conceived one of the world's most magnificent buildings to house books given as the world's first non-monastic public library. That building is the magnificently expressive, long, porticoed Library across from the Doge's Palace. It gave new form to the politically active Piazzetta space around the corner from the Piazza, next to the water.
Often I have wondered if Sansovino's two-story design could have been a gesture to express the essentially Greek contents of the collection, and Venice's assimilation of that ancient civilization, even though his bold sculptural forms follow those of the Roman Renaissance and of ancient Rome.
In Sansovino's Library, the arched reading room windows upstairs repeat the arcade rhythm below, facing, as in ancient libraries, the fresh, bright light of the morning. Dazzling, the light, reflected from the water, brightens the upper rooms as well as each luxury shopkeeper's share of that community walkway below, newly swept each morning.
Sansovino's son Francesco, in his 1561 guidebook to Venice, explains that his father intended his design for the Library to surround all of Piazza San Marco, including the recently rebuilt north wing.
But to erect bays of the Library's porticoed fa,cade on each face of the corner toward San Marco, Jacopo Sansovino had to solve the problem of a corner filled with the massive shaft of the Campanile.
By beginning the Library five meters closer to the water, he liberated the Campanile, making it a free-standing monument; and, by moving the Piazza's south wall back about 20 meters, he broadened and regularized the whole trapezoidal Piazza space.
A master of political diplomacy, Sansovino had the backing of several close friends among the Procurators. In turn, he rewarded his employers by increasing the profits on their properties, raising the rents for the shopkeepers behind the arcades, relocating hostels and a bakery.
The Piazzetta area welcomes one coming to the city. Disembarking at the head of the Grand Canal, a late-16th-century ambassador would find himself embraced by the arcaded walls of an open-air room.
With the shimmering-surfaced Doge's Palace on the right, and the brilliant-white, richly sculptured Istrian-stone fa,cade of the new Library at the left, he would look beyond to San Marco and the long Piazza.
Was this a new Rome, a new Athens, a new Constantinople? Was this room a forum, an agora (Greek marketplace of ideas)?
A 16th-century Venetian would have answered yes to all those questions, for the Venetian Republic saw itself as heir to the best in the ancient civilizations.
By 1663 later architects had fulfilled Sansovino's plan. Baldassare Longhena succeeded Vincenzo Scamozzi in rebuilding the south and west sides, adding one further story to provide at last for the apartments for the Procurators. These had been postponed when the Procurators decided to rebuild the city's central civic area with the Library facing the Doge's Palace.
When Napoleon, with the help of the Modenese architect Giuseppe Maria Soli, remade the west wing for a ballroom in the early 19th century, he transformed Piazza San Marco into what he called ``the most beautiful drawing room in Europe.''
Bonaparte probably thought, not just of the shape of the space, but of its brilliant-white, light-filled, ebullient walls, which frame San Marco under shifting blue-gray skies.
But for us, the secret to the eloquence of the space has to be rather the elegant, welcoming shelter of those expansive, wide-open, wind-breaking walkways. There, almost forever, a more cosmopolitan throng has enjoyed life in the shaded sunshine - safe from vicissitudes of weather, safe from dive-bombing pigeons.