Information about Milan.
During the Middle Ages, Milan prospered as a centre of trade due to its position. The war of conquest by Frederick I Barbarossa brought the destruction of much of Milan in 1162. Milan took the lead role in the formation of the Lombard League, formed in 1167. The war between the German emperor and the Italian communes continued for years, ending with the Italian victory at the battle of Legnano. As a result of the independence that the Lombard cities gained in the Peace of Constance in 1183, Milan became a duchy. In 1208 Rambertino Buvalelli served a term as podestà of the city, in 1242 Luca Grimaldi, and in 1282 Luchetto Gattilusio. The position was a dangerous one: in 1252 Milanese heretics assassinated the Church's Inquisitor, later known as Saint Peter Martyr, at a ford in the nearby contado; the killers bribed their way to freedom, and in the ensuing riot the podestà was almost lynched. In 1256 the archbishop and leading nobles were expelled from the city.
Until 1259, Milan was a free commune, in practice an oligarchy, that elected its own podestà. The Della Torre family gained sustained power in 1240, when Pagano della Torre was elected podestà. After Pagano's death, his nephew Martino was elected, but at the end of his tenure, Martino perpetrated a coup d'état and proclaimed himself the first "Lord of Milan", establishing the city's Signoria (Italian for "Lordship"). Another powerful family were the Viscontis, who eventually became Dukes of Milan.
On 22 July 1262 Ottone Visconti was made archbishop of Milan by Pope Urban IV, against the candidacy of Raimondo della Torre, Bishop of Como. The latter thus started to publicise allegations of the Visconti's closeness to the heretic Cathars and charged them of high treason: the Visconti, who accused the Della Torre of the same crimes, were then banned from Milan and their properties confiscated. The ensuing civil war caused more damage to Milan's population and economy, lasting for more than a decade. Ottone Visconti unsuccessfully led a group of exiles against the city in 1263, but after years of escalating violence on all sides, in the Battle of Desio (1277) he won the city for his family. The Visconti succeeded in ousting the della Torre permanently, and proceeded to rule Milan and its possessions until the 15th century.
Much of the prior history of Milan was the tale of the struggle between two political factions: the Guelphs and the Ghibellines. Most of the time the Guelphs were successful in the city of Milan. Eventually, however, the Visconti family were able to seize power (signoria) in Milan, based on their "Ghibelline" friendship with the German Emperors. In 1395, one of these emperors, Wenceslas (1378–1400), raised the Milanese to the dignity of a duchy. Also in 1395, Gian Galeazzo Visconti became duke of Milan. The Ghibelline Visconti family was to retain power in Milan for a century and a half from the early 14th century until the middle of the 15th century.
In 1447 Filippo Maria Visconti, Duke of Milan, died without a male heir; following the end of the Visconti line, the Ambrosian Republic was enacted. The Ambrosian Republic took its name from St. Ambrose, popular patron saint of the city of Milan. Both the Guelph and the Ghibelline factions worked together to bring about the Ambrosian Republic in Milan. Nonetheless, the Republic collapsed when, in 1450, Milan was conquered by Francesco Sforza, of the House of Sforza, which made Milan one of the leading cities of the Italian Renaissance.
In 1714, with the end of the War of the Spanish Succession, Milan and its territories were conquered by the Austrian Empire. In 1814, the Duchy of Milan was integrated into the new Kingdom of Lombardy-Venetia, part of the Habsburg territories.