What is the legend of Santiago?

The legend of Santiago says that the Apostle Santiago, after his preaching in Roman Hispania, was martyred on his return to Jerusalem, around the 1st century AD. After being beheaded by King Herod Agrippa I, his disciples Teodoro and Atanasio decided to move his body to Galicia, the epicenter of his preaching.

Several centuries later, around the years 813-820, the hermit Paio discovered his tomb guided by some lights, which led to the pilgrimages to Santiago de Compostela.