The city used to be a major European political centre. From 1563, it was the capital of the Duchy of Savoy, then of the Kingdom of Sardinia ruled by the House of Savoy, and the first capital of the Kingdom of Italy from 1861 to 1865. Turin is sometimes called "the cradle of Italian liberty" for having been the birthplace and home of notable individuals who contributed to the Risorgimento, such as Cavour. Even though much of its political significance and importance had been lost by World War II, Turin became a major European crossroad for industry, commerce and trade, and is part of the famous "industrial triangle" along with Milan and Genoa. Turin is ranked third in Italy, after Milan and Rome, for economic strength. With a GDP of $58 billion, Turin is the world's 78th richest city by purchasing power. As of 2018, the city has been ranked by GaWC as a Gamma World city. Turin is also home to much of the Italian automotive industry, with the headquarters of Fiat, Lancia and Alfa Romeo.