Vicenza is a thriving and cosmopolitan city, with a rich history and culture, and many museums, art galleries, piazzas, villas, churches and elegant Renaissance palazzi. With the Palladian Villas of the Veneto in the surrounding area, and his renowned Teatro Olimpico (Olympic Theatre), the "city of Palladio" has been enlisted as UNESCO World Heritage Site since 1994.
In December 2008, Vicenza had an estimated population of 115,927, and a metropolitan area of 270 000. Vicenza is the third-largest Italian industrial centre as measured by the value of its exports, and is one of the country's wealthiest cities, in large part due to its textile and steel industries, which employ tens of thousands. Additionally, about one fifth of the country's gold and jewelry is made in Vicenza, greatly contributing to the city's economy. Another important sector is the engineering/computer components industry (Federico Faggin, the microprocessor's co-inventor, was born in Vicenza).
Vicentia was settled by the Italic Euganei tribe and then by the Paleo-Veneti tribe in the 3rd and 2nd centuries BC. The Romans allied themselves with the Paleo-Veneti in their fight against the Celtic tribes that populated north-western Italy. The Roman presence in the area grew exponentially over time and the Paleo-Veneti (whose culture mirrored Etruscan and Greek values more so than Celtic ones) were gradually assimilated. In 157 BC, the city was a de facto Roman centre and was given the name of 'Vicetia' or 'Vincentia', meaning "victorious".
The population of Vicentia received Roman citizenship in 49 BC. The city had some importance as a way-station on the important road from Mediolanum (Milan) to Aquileia, near Tergeste (Trieste), but it was overshadowed by its neighbor Patavium (Padua). Little survives of the Roman city, but three of the bridges across the Bacchiglione and Retrone rivers are of Roman origin, and isolated arches of a Roman aqueduct exist outside the Porta Santa Croce.
During the decline of the Western Roman Empire, Heruls, Vandals, Alaric and his Visigoths, as well as the Huns laid waste to the area, but the city recovered after the Ostrogoth conquest in 489 AD, before passing to Byzantine rule soon after. It was also an important Lombard city and then a Frankish centre. Numerous Benedictine monasteries were built in the Vicenza area, beginning in the 6th century.
In 899, Vicenza was destroyed by Magyar raiders.
In 1001, Otto III handed over the government of the city to the bishop, and its communal organization had an opportunity to develop, separating soon from the episcopal authority. It took an active part in the League with Verona and, most of all, in the Lombard League (1164–1167) against Emperor Frederick I Barbarossa compelling Padua and Treviso to join: its podestà, Ezzelino II il Balbo, was captain of the league. When peace was restored, however, the old rivalry with Padua, Bassano, and other cities was renewed, besides which there were the internal factions of the Vivaresi (Ghibellines) and the Maltraversi (Guelphs).
The tyrannical Ezzelino III from Bassano drove the Guelphs out of Vicenza, and caused his brother, Alberico, to be elected podestà (1230). The independent commune joined the Second Lombard League against Emperor Frederick II, and was sacked by that monarch (1237), after which it was annexed to Ezzelino's dominions. On his death the old oligarchic republic political structure was restored -a consiglio maggiore ("grand council") of four hundred members and a consiglio minore ("small council") of forty members - and it formed a league with Padua, Treviso and Verona. Three years later the Vicentines entrusted the protection of the city to Padua, so as to safeguard republican liberty; but this protectorate (custodia) quickly became dominion, and for that reason Vicenza in 1311 submitted to the Scaligeri lords of Verona, who fortified it against the Visconti of Milan.
Vicenza was a candidate to host the Council of Trent.
The 16th century was the time of Andrea Palladio, who left many outstanding examples of his art with palaces and villas in the city's territory, which before Palladio's passage, was arguably the most downtrodden and esthetically lacking city of the Veneto.
After 1797, under Napoleonic rule, it was made a duché grand-fief (not a grand duchy, but a hereditary (extinguished in 1896), nominal duchy, a rare honor reserved for French officials) within Napoleon's personal Kingdom of Italy for general Caulaincourt, also imperial Grand-Écuyer.
After 1814, Vicenza passed to the Austrian Empire. In 1848, however, the populace rose against Austria, more violently then in any other Italian centre apart from Milan and Brescia (the city would receive the highest award for military valour for the courage displayed by revolutionaries in this period). As a part of the Kingdom of Lombardy-Venetia, it was annexed to Italy after the 3rd war of Italian independence.
Vicenza's area was a location of major combat in both World War I (on the Asiago plateau) and World War II (a focal centre of the Italian resistance), and it was the most damaged city in Veneto by Allied bombings, including many of its monuments; the civil victims were over 2,000. After the end of the latter, what followed was a period of depression following the devasatation caused by two world conflicts. In the 1960s the whole central part of Veneto, witnessed a strong economic development caused by the emergence of small and medium family businessess, ranging in a vast array of products (that often emerged illegally) that paved the way for what would be known as the "miracolo del Nord-est" (Miracle of the North-east). In the following years, the economic development grew vertiginously. Huge industrial areas sprouted around the city, massive and disorganised urbanisation and employment of foreign immigrants increased.
Vicenza is home to the United States Army post Caserma Ederle (Camp Ederle), also known as the U.S. Army Garrison Vicenza. In 1965, Caserma Ederle became the headquarters for the Southern European Task Force, which includes the 173d Airborne Brigade. In January 2006, the European Gendarmerie Force was inaugurated in Vicenza.