There are many remarkable stories about St. Patrick and a bell he used to call the people of Ireland to prayer.
According to various accounts of his life, St. Patrick frequently used a handbell wherever he went and "whenever St. Patrick had set up a new Christian community or parish somewhere in Ireland, he would choose one of his disciples to lead it after he left, and present them with a bell to call the parishoners to prayer, and to use during religious ceremonies."
In addition to serving a practical function, St. Patrick's bell was also used as a tool for spiritual battle.
In a 19th-century book on St. Patrick's life, the author explains how St. Patrick used the bell against evil spirits that tormented him on the mountain of Croagh Patrick.
Then he rang his bell, the bell which he appears to have carried with him everywhere and which no doubt was specially blessed. "To drive all demons from the upper air." Then he threw the bell amongst [the evil spirits] in holy anger, so that a piece was broken from it.
The Catholic Church has preserved this ability of bells to drive out demons in the Roman Ritual blessing of bells, where the priest prays, "At its sound let all evil spirits be driven afar."
There are some legends that say St. Patrick drove out all the serpents from Ireland using his bell, which could be referring to evil spirits, or the snakes that no longer inhabit the Emerald Isle.
St. Patrick's bell is currently on display at the National Museum in Dublin, Ireland.