It's been around since the dawn of modern civilization. From the moment humans were allowed to express their ideas in art, writing, poetry, or images, censorship was in place. Censorship is defined as the suppression of all or part of a publication, play, or film considered offensive - or - the suppression or attempted suppression of something regarded as objectionable. .
One of the earliest modern instances of large censorship was the great battle between Copernicus and the Church. Copernicus believed that the earth revolved around the sun, which was in fact true. At the time, the Church believed heavily that the Earth was the center of everything, and saying something of that nature was sacrilegious. We know now that Copernicus was in fact right. Unfortunately, the Church threatened Copernicus and his followers so his works were never widely published. Perhaps if it wasn't for Censorship, the world might be a different place then it is today.
Another example of Censorship is the great Censorship of cubism and cubic art from Nazi Germany in the 1930's. This is when Hitler, then ruler of Germany, sanctioned the banning and burning of all "art decadent to the senses." On top of artist's paintings, he also burned hundreds of thousands of books before and during World War II. .
A modern, more recent example of censorship is the current battle over "fair use" and technology. For instance, videogames are currently under attack by the modern press and government because they are said to "stimulate children into violent acts" and to "desensitize children to violence and gore." As a videogame player for 10 years, I can say that I am still as scared as a bullet as any other man after getting shot in the face thousands of times. (Virtually, that is) Sadly, many want videogames banned if they contain mature violence and gore. Already, Wal-Mart will not sell a particularly violent video game, Grant Theft Auto: III because of its general all around "going postal-ness.
