Please answer a question about the following article about Mexico City:

The Museo Soumaya, named after the wife of Mexican magnate Carlos Slim, has the largest private collection of original Rodin sculptures outside Paris. It also has a large collection of Dalí sculptures, and recently began showing pieces in its masters collection including El Greco, Velázquez, Picasso and Canaletto. The museum inaugurated a new futuristic-design facility in 2011 just north of Polanco, while maintaining a smaller facility in Plaza Loreto in southern Mexico City. The Colección Júmex is a contemporary art museum located on the sprawling grounds of the Jumex juice company in the northern industrial suburb of Ecatepec. It is said to have the largest private contemporary art collection in Latin America and hosts pieces from its permanent collection as well as traveling exhibits by leading contemporary artists. The new Museo Júmex in Nuevo Polanco was slated to open in November 2013. The Museo de San Ildefonso, housed in the Antiguo Colegio de San Ildefonso in Mexico City's historic downtown district is a 17th-century colonnaded palace housing an art museum that regularly hosts world-class exhibits of Mexican and international art. Recent exhibits have included those on David LaChapelle, Antony Gormley and Ron Mueck. The National Museum of Art (Museo Nacional de Arte) is also located in a former palace in the historic center. It houses a large collection of pieces by all major Mexican artists of the last 400 years and also hosts visiting exhibits.

How many years worth of art does the Museum in the historic center hold?
400