World Marathon Majors was created in 2006.
IAAF World Half Marathon Championships was created in 1992.
The five marathon "majors" are Boston, Berlin, Chicago, London and New York. Other, but by no means an exaustive list, marathons that have large participation include the Marine Corp Marathon, LA Marathon and the Paris Marathon.
Of course there are more than five. But five major Marathon races held in the cities of Berlin, Boston, Chicago, London, and New York City are together called the "World Marathon Majors."
New York City Marathon was created in 1970.
Majors Airport was created in 1942.
Frankfurt Marathon was created in 1981.
Cardiff Marathon was created in 1981.
Nagoya Marathon was created in 1984.
Gusher Marathon was created in 2010.
Rotterdam Marathon was created in 1981.
Checker Marathon was created in 1961.
Oslo Marathon was created in 2004.