Argentina declared independent from Spain in 1816, and achieved it in a War led by José de San Martín in 1818. Many immigrants from Europe came to the country. By the 1920s it was the 7th wealthiest country in the world, but it began a decline after this. In the 1940s, following the "infamous decade" where the country's politics were not stable, Juan Peron came to power. Peron was one of the most important people in the country's history and many politicians today call themselves Peronist. Peron was forced out of power in 1955. After spending years in exile he returned to power in the 1970s.