Our Intercessors Before God:
Few practices of the Catholic Church are so misunderstood today as devotion to patron saints. From the earliest days of the Church, groups of the faithful (families, parishes, regions, countries) have chosen a particularly holy person who has passed on to intercede for them with God. Seeking the intercession of a patron saint does not mean that one cannot approach God directly in prayer; rather, it's like asking a friend to pray for you to God, while you also pray—except, in this case, the friend is already in Heaven, and can pray to God for us without ceasing. It's the communion of saints, in actual practice.
Intercessors, Not Mediators:
Some Christians argue that patron saints detract from the emphasis on Christ as our Savior. Why approach a mere man or woman with our petitions when we can approach Christ directly? But that confuses Christ's role as mediator between God and man with the role of intercessor. Scripture urges us to pray for one another; and, as Christians, we believe that those who have died still live, and therefore are capable of offering prayers as we do.
In fact, the holy lives lived by the saints are themselves testimony to the saving power of Christ, without Whom the saints could not have risen above their fallen nature.
The History of Patron Saints:
The practice of adopting patron saints goes back to the building of the first public churches in the Roman Empire, most of which were built over the graves of martyrs. The churches were then given the name of the martyr, and the martyr was expected to act as an intercessor for the Christians who worshiped there.
Soon, Christians began to dedicate churches to other holy men and women—saints—who were not martyrs. Today, we still place some relic of a saint inside the altar of each church, and we dedicate that church to a patron. That's what it means to say that your church is St. Mary's or St. Peter's or St. Paul's.
How Patron Saints Are Chosen:
Thus, the patron saints of churches, and more broadly of regions and countries, have generally been chosen because of some connection of that saint to that place—he had preached the Gospel there; he had died there; some or all of his relics had been transferred there. As Christianity spread to areas with few martyrs or canonized saints, it became common to dedicate a church to a saint whose relics were placed in it or who was especially venerated by the founders of the church. Thus, in the United States, immigrants often chose as patrons the saints that had been venerated in their native lands.
Patron Saints for Occupations:
As the Catholic Encyclopedia notes, by the Middle Ages, the practice of adopting patron saints had spread beyond churches to "the ordinary interests of life, his health, and family, trade, maladies, and perils, his death, his city and country. The whole social life of the Catholic world before the Reformation was animated with the idea of protection from the citizens of heaven." Thus, Saint Joseph became the patron saint of carpenters; Saint Cecilia, of musicians; etc. Saints were usually chosen as patrons of occupations that they had actually held or that they had patronized during their lives.
Patron Saints for Diseases:
The same is true of patron saints for diseases, who often suffered from the malady assigned to them or cared for those who did. Sometimes, though, martyrs were chosen as the patron saints of diseases which were reminiscent of their martyrdom. Thus, Saint Agatha, who was martyred c. 250, was chosen as the patron of those with diseases of the breast, since her breasts were cut off when she refused marriage to a non-Christian.
Often, such saints are chosen too as a symbol of hope. The legend of Saint Agatha attests that Christ appeared to her as she lay dying and restored her breasts that she might die whole.
Personal and Familial Patron Saints:
All Christians should adopt their own patron saints—first and foremost being those whose name they carry or whose name they took at their Confirmation. We should have a special devotion to the patron saint of our parish, as well as the patron saint of our country and the countries of our ancestors.
It's also a good practice to adopt a patron saint for your family and to honor him or her in your house with an icon or statue. The saints are powerful intercessors, and, in this day and age when they are so often neglected, we could use their prayers more than ever.