" 

  
 It wasn't called by the ""catholic church"" but by Constantine to create a single imperial religion that would unite all the disparate religious groups that existed within the Roman Empire.  What the world ended up with was a catholic churh that was am amalgam of Sol Invictus (Roman) Mithras (Persian) Judaism (Palestine) with Greek and Northern European belief thrown in to make up something that would be acceptable to everyone throughout the Empire."