The tradition dates to Pope Callixtus II in 1122 and was made perpetual by Pope Alexander III in 1179. During a Holy Year a plenary indulgence is granted, once per day, to pilgrims who visit the cathedral, pray the Our Father and Creed for the intentions of the Pope, and confess and receive Communion within about 15 days before or after.
The Compostela certificate rules do not change: at least the last 100 km on foot or horseback, or 200 km by bicycle, with a stamped credential. The next Compostela Holy Years after 2027 are 2032 and 2038.