Today, the medieval high street of Barcelona, an early example of town planning, runs between the Romanesque Capella d'en Marcús and Passeig del Born. It initially emerged in the 12th century, when it extended northeast from the city walls towards the sea. The street became renowned as the most desirable address for the city's wealthy merchants classes, and the grand mansions that still stand today, many of which now house the Museu Picasso, mostly date back to the 14th and 15th centuries.