Why would pilgrims have gone to visit Thomas Beckets shrine at Canturbury

The pilgrims would often visit Thomas Becket's shrine at Canterbury because Becket was considered a martyr and a hero by the church. He defended the church against the oppression of King Henry II and was killed because of it. Because of this, a shrine was created in his honor and became a place where many come to gain spiritual credit. Monks from the monasteries did up the shrine so that it became suitable for worshippers that came. Eventually the place officially became a Holy Land where many pilgrims come to.