"Karlskirche" --or St. Charles Church -- is the commonly used name for the Rektoratskirche St. Karl Borromäus, an 18th century structure on the River Wien in Vienna, Austria. The Baroque structure was commissioned by Charles VI, King of Bohemia, to honor Charles Borromeo (1538 - 1584), saint of bishops, catechists, and seminaries, who was cannonized in the 17th century for healing and feeding tens of thousands of plague victims in Milan after the ruling class fled in fear.
In 1713, when the last great Plague began to sweep through Vienna, as a prayerful pledge King Charles VI vowed to build Karlskirche in the saint's honor if the plague left the city. By 1715 the Plague had ended and construction of the church began on the bank of the River Wien.