According to local history, Medir was a farmer who helped Bishop Severus escape Roman persecution. Legend says that broad beans planted by Medir grew instantly to hide the bishop's path. Today, the Romanesque chapel in Collserola remains a key site for the annual pilgrimage.

The modern celebration was shaped in 1830 by Josep Vidal i Granés, a baker who started the tradition of riding to the chapel on horseback. This evolved into the famous candy-throwing parades organized by local groups in Barcelona and Sant Cugat.