The Teenage Mutant Ninja Turtles (often shortened to the TMNT or Ninja Turtles) are a fictional superhero quartet of anthropomorphic turtle brothers, trained in the ancient art of ninjitsu ninjas that appear in a self-titled franchise consisting of comic books, shows, films, and other tie-in products. The characters were created in 1984 by comic book writer-artist team Peter Laird and Kevin Eastman, who named the four turtles after Italian Renaissance artists, and published the characters' adventures in comic books published by Mirage Studios. Within their stories, the turtles were trained in the Japanese martial art of ninjutsu by their adoptive father Splinter, an anthropomorphic rat sensei. From their home in the sewers of New York City, they battle petty criminals, evil overlords, mutated creatures, and alien invaders while attempting to remain hidden from society. During the peak of the franchise's popularity in the late 1980s and early 1990s, it gained worldwide success and fame.