In the Time of Gargoyles

Imagine an age of unabashed fear within a society polarized by the isolation of class and status. Add to this equation the personification of good vs. evil or heaven vs. hell mixed with the prospect of eternal damnation as symbolized by the ever-imposing gargoyles of the medieval ages.
By definition, gargoyles are merely a carved stone drain-spout with what is known as a "grotesque" surface decoration or ornament attached. As a point of interest and fact, a grotesque, also referred to as a chimeras, may stand alone as decoration but may not be described as a gargoyle without benefit of the necessary drain-spout.
The name gargoyle is from the French derivative of the word gargouille meaning "throat" or "gullet" with a Latin root gar "to swallow" and a prefix for words suggesting the gurgling sound of water.
Before the 18th century, drain-spouts were the standard method for dispersing the rainwater collected on the roofs of tall buildings. Drain-spouts extended or protruded from the roof at the parapet level, whether or not then further adorned by a grotesque. Gargoyles later fell out of favor with the advent of the more logical down spout for water drainage.
Gargoyles were meant to provide visual warnings about the evils of a carnal world while also encouraging the safety and protection of the church as manifested in the Christian religion. During this period of rampant illiteracy, gargoyles were meant as a literal etched in stone instrument to "scare the hell out of its beholders".
Keep in mind that the medieval age was a time of wide held belief in demons, monsters, and the supernatural. For instance, people did believe that those gargoyles resembling griffins, with the body of a lion and the head and wings of an eagle, came alive at night to fly around and protect the villagers.
Cathedrals such as Notre Dame in Paris, one of about 100 medieval cathedrals in France, and the Dornach Cathedral in Dornach Scotland are famous for the many ornately carved gargoyles. There are certainly a wide variety of gargoyles on ancient cathedrals all throughout Europe but whether the image is half man and half beast or hideous monster it seems gargoyles may have distinct pagan roots. It is probable the church used these familiar symbols as a tool to build a figurative bridge aiding in the conversion of people from the pagan belief to Christian.
Sources:
Wilkipedia
Northstar Gallery