In 1420 it was conquered by the Republic of Venice. In 1511 it was the seat of a short civil war, which was followed by an earthquake and a plague. Udine remained under Venetian control until 1797, being the second largest city in the state. After the short French domination which ensued, it was part of the Austrian-puppet Lombardy-Venetia Kingdom, and was included in the newly formed Kingdom of Italy in 1866.
During World War I, after the defeat in the battle of Caporetto, Udine became the seat of the Italian High Command and was nicknamed "Capitale della Guerra" ("War Capital"). After the war it was made capital of a short-lived province (Provincia del Friuli) which included the current provinces of Gorizia, Pordenone and Udine. After September 8 1943, when Italy surrendered to the Allies in World War II, the city was under direct German administration, which ceased in April 1945.
In 2007, there were 97,880 people residing in Udine itself(whereas the greater area has a population double its size), located in the province of Udine, Friuli Venezia Giulia, of whom 46.9% were male and 53.1% were female. Minors (children ages 18 and younger) totalled 14.36 percent of the population compared to pensioners who number 24.27 percent. This compares with the Italian average of 18.06 percent (minors) and 19.94 percent (pensioners). The average age of Udine residents is 47 compared to the Italian average of 42. In the five years between 2002 and 2007, the population of Udine grew by 1.48 percent, while Italy as a whole grew by 3.56 percent. The current birth rate of Udine is 9.13 births per 1,000 inhabitants compared to the Italian average of 9.45 births.
As of 2006, 90.90% of the population was of Italian descent. The largest immigrant group came from other European nations (particularly those from Albania, Romania and Serbia): 5.37%, followed by sub-saharan Africa (mostly from Ghana): 1.65%, and North African: 0.77%. Approximately 1 in 5 babies born in Udine has at least one foreign parent in which Albanian and Romanian births constitute the largest.
The old residence of the patriarchs of Aquileia was erected by Giovanni Fontana in 1517 in place of the older one destroyed by an earthquake in 1511. Under the Austrians it was used as a prison. In the cathedral archives was formerly preserved a recast of the Visigothic code of laws in a manuscript known as the Codex Utinensis, which was fortunately printed before it was lost. (See Breviary of Alaric).
The church dedicated to St. Mary of the Castle is probably the oldest in Udine, judging from extant fragments dating back to the Lombard era. It lost its parish status in 1263, when it was annexed to the larger parish of Saint'Odorico (now the Cathedral). It has been renovated many times over the centuries: the façade, for example, was entirely rebuilt after the catastrophic earthquake of 1511. Its three naves preserve the suggestive atmosphere of silence and contemplation, which is often found in old churches. The Venetian Governor, Tommaso Lippomano, commissioned the Venetian Gothic portico with steps and ramps leading down the hill in 1487.
In the principal square (Piazza della Libertà) stands the town hall (Loggia del Lionello) built in 1448-1457 in the Venetian-Gothic style opposite a clock tower (Torre dell’Orologio) resembling that of the Piazza San Marco at Venice. It was begun in 1448 on a project by Nicolò Lionello, a local goldsmith, and was rebuilt following a fire in 1876. The new design was projected by the architect Andrea Scala.
Opposite the Loggia del Lionello is the Loggia di San Giovanni, a Renaissance structure designed by Bernardino da Morcote. Other noteworthy monuments in the square are the Fountain by Giovanni Carrara, an architect from Bergamo (1542); the Columns bearing the Venetian Lion and the Statue of Justice (1614), the statues of Hercules and Cacus and the Statue of Peace (1819) which was donated to Udine by Emperor Francis I to commemorate the peace Treaty of Campoformido.
The Cathedral of Udine is an imposing edifice whose construction started in 1236, on a Latin cross-shaped plan with three naves and chapels along the sides. The church was consecrated in 1335 as Santa Maria Maggiore. At the beginning of th 18th century a radical transformation project involving both the exterior and the interior was undertaken at the request and expense of the Manin family. The Baroque interior has monumental dimensions and contains many works of art by Tiepolo, Amalteo, and Ludovico Dorigny. On the ground floor of the bell tower (built from 1441 over the ancient baptistry) is a chapel which is completely adorned with frescoes by Vitale da Bologna (1349).
The center of Udine is dominated by the Castle, built by the Venetians from 1517 over a Lombard fortification ruined by an earthquake in 1511. The current Renaissance appearance dates from the intervention of Giovanni da Udine, who finished the works starting from 1547. The castle houses one of the most ancient Parliament Halls of Europe.