St. Anthony remains one of the most popular Catholic saints, as he is frequently invoked for help in finding lost things.
The primary reason behind this patronage is a legend about his life that was told throughout the Middle Ages and up to the present day.
Fr. Ubaldus da Rieti narrates this story in his Life of St. Anthony:
While he was thus employed occurred a memorable incident worthy to be related. [St. Anthony] had with him an exposition on the Psalms written by himself in which he had gathered the best part of the Old and New Testaments, and from which, as from a fountain, he drank of that celestial wisdom which enabled him to explain theological questions and gave weight and force to his sermons for the benefit of souls.
In other words, it was his favorite book.
St. Anthony loses his book
The book was subsequently stolen by a novice, who left the monastery. St. Anthony wanted the book back, but had no idea where the novice fled.
St. Anthony immediately turned to God for help:
A novice tired of the religious life resolved to return to the world, and having seen the book containing the exposition on the Psalms, stole it and fled from the monastery. The saint grieved at the loss of a book so useful and necessary to him, immediately had recourse to prayer, requesting the Lord not only to have mercy on the unhappy young man, but also to induce him to restore the stolen book.
According to the legend, God heard St. Anthony's prayer and commanded the devil to intervene:
His prayer was heard by the Lord. The devil, compelled by divine command, appeared to the young man in the form of a horrible monster and stopped him, saying, "Go back and restore immediately that which you have stolen, otherwise I will kill you and throw you into the river."
The novice was frightened by the sight and returned to the monastery, returning the book and humbling himself before St. Anthony.
St. Anthony had mercy on him and encouraged him to remain steadfast in his service of the Lord.
Ever since that story was spread, St. Anthony has been honored as the patron saint of lost things.
