Saints often become the patrons of places where they were born or had been active. However, there were cases in Medieval Europe where a city which grew to prominence and obtained for its cathedral the remains or some relics of a famous saint who had lived and was buried elsewhere, thus making them the city's patron saint – such a practice conferred considerable prestige on the city concerned. In Latin America and the Philippines, Spanish and Portuguese explorers often named a location for the saint on whose feast or commemoration they first visited the place, with that saint naturally becoming the area's patron. Professions sometimes have a patron saint owing to that individual being involved somewhat with it, although some of the connections were tenuous. Lacking such a saint, an occupation would have a patron whose acts or miracles in some way recall the profession. For example, when the previously unknown profession of photography appeared in the 19th century, Saint Veronica was made its patron, owing to how her veil miraculously received the imprint of Christ's face after she wiped off the blood and sweat.
The veneration or "commemoration" and recognition of patron saints or saints in general is found in Roman Catholicism, Eastern Catholicism, Eastern Orthodoxy, Oriental Orthodoxy, and among some Lutherans and Anglicans. Catholics believe that patron saints, having already transcended to the metaphysical, are able to intercede effectively for the needs of their special charges. It is, however, generally discouraged in most Protestant branches such as Calvinism, where the practice is considered a form of idolatry.
Islam
Although Islam has no codified doctrine of patronage on the part of saints, it has nevertheless been an important part of both Sunni and ShiaIslamic tradition that particularly important classical saints have served as the heavenly advocates for specific Muslim empires, nations, cities, towns, and villages. Martin Lings wrote: "There is scarcely a region in the empire of Islam which has not a Sufi for its Patron Saint." As the veneration accorded saints often develops purely organically in Islamic climates, in a manner different from Catholic and Eastern Orthodox Christianity, "patron saints" are often recognized through popular acclaim rather than through official declaration. Traditionally, it has been understood that the patron saint of a particular place prays for that place's wellbeing and for the health and happiness of all who live therein. However, the Wahhabi and Salafi movements within Sunnism have latterly attacked the veneration of saints, which they claim are a form of idolatry or shirk. More mainstream Sunni clerics have critiqued this argument since Wahhabism first emerged in the 18th century. The critiques notwithstanding, widespread veneration of saints in the Sunni world declined in the 20th century under Wahhabi and Salafi influence.
