Timeline.
January 2008 - The Treaty of the Liberty Bell is negotiated. Charles Xavier agreed to disband all X-Men organizations in an exchange for a government guarantee that all official discriminatory and physical action being taken against mutants would cease. The Mutant Institute now becomes known to the public, though the government agrees to allow Xavier to keep its location a secret from the public as a necessary safety precaution for its students.
October 2007 - The X-Men defeat Magneto's Brotherhood of Mutants in a battle taking place in rural Mexico, which claims many lives on both sides. Magneto is banished to a high-security prison located in Greenland.
July 2005 - Charles Xavier makes a decision to re-locate his school and headquarters to a new, secure location (New Salem, New York). With more and more mutants seeking a safe haven by the day, Xavier realizes that the Institute needs to go underground in order to successfully protect its students.
April 2005 - The United States leads the way in creating anti-mutant laws. Mutants are required to register with the government. Those who fail to do so are placed under arrest and detained at camps especially designed to hold Mutants. As the months pass, more and more legislation is passed: mutants are not allowed to attend school with humans; businesses are given permission to fire mutant employees, etc. The world becomes a generally unpleasant place for mutants.
February 2, 2005 - The Brotherhood sponsors a day of global terrorism against humans. Attacks of a massive scale are made on major cities in the United States, Canada, France, Germany, England, Italy, Russia, Chile, South Africa, Egypt, China, South Korea, and Japan. World governments are suddenly united together for a common cause: to deal with the Mutant problem.
1999 - Despite its reputation in the media, the Mutant Institute continues to grow, as do the ranks of the X-Men and Magneto's Brotherhood. Though many mutants still attempt to live a "normal" life with the rest of human society, every year more and more of them seek the solace and companionship that comes with the company of other mutants.
June 1996 - The British government refuses to work with the X-Men any longer. Though the official reasoning is unknown, it is clear that anti-mutant sentiments among members of the Prime Minister's cabinet and general populace are to blame. Slowly but surely, other nations follow suit. Soon, "X-Men" is very much a dirty word.
1990 - Realizing the demand for those with mutant powers to protect normal humans are are becoming occasional victims of rogue mutants, Xavier forms the X-Men. At first, the group is meant to work with world governments in their efforts to protect citizens.
1985 - Erik Lansherr - a mutant who goes by the name of Magneto and an old friend of Charles Xavier - creates the Brotherhood of Mutants. The organization is centered in London and consists of mutants who believe themselves to be superior to humans. All members of the Brotherhood refuse to register with any human government, and are also reputed for random acts of violence against humans. The numbers of the organization are small, but grow steadily over the coming years.
November 1982 - Charles Xavier creates The Mutant Institute, where he helps young (and old) mutants learn to control their powers and function in a normal society. It is located in San Diego, California. The school opens with 8 pupils and three professors.
August 1980 - Countries all over the world draft Mutant Registration Acts, wherein all known mutants are required to register with the government.