Todays medieval saint is James the Greater. Pilgrims would aspire to reach his shrine in Santiago de Compostela in Galicia on this day by following the Way of St. James. Those who made this pilgrimage would wear James symbol – a scallop shell. https://en.wikipedia.org/wiki/Camino_de_Santiago
https://en.wikipedia.org/wiki/James,_son_of_Zebedee