The series began in 1926, when Knute Rockne became one of the first coaches east of the Mississippi River to take his team to the West Coast. The next four games then alternated between Soldier Field and Los Angeles' Memorial Coliseum, with the first game played taking place at Notre Dame Stadium in 1931.
The origin of Notre Dame's nickname has never been definitively explained.
One story suggests the name was born in 1899 with Notre Dame leading Northwestern 5-0 at halftime of a game in Evanston, Ill. The Wildcat fans supposedly began to chant, "Kill the Fighting Irish, kill the Fighting Irish," as the second half opened. Another story suggests the nickname originated at halftime of the Notre Dame-Michigan game in 1909. Notre Dame trailed and one player yelled to his teammates, many with Irish names, "What's the matter with you guys? You're all Irish and you're not fighting worth a lick." Notre Dame came back to win the game and the press, after overhearing the remark, reported the game as a victory for the "Fighting Irish."
The most accepted explanation is that the press coined the nickname as a characterization of Notre Dame athletic teams, their never-say-die fighting spirit and their Irish qualities of grit, determination and tenacity. Notre Dame alumnus Francis Wallace popularized it in his New York Daily News columns in the 1920s.
Until 1912, teams at the University of Southern California were known as the Methodists or the Wesleyans. But university officials were unhappy with both nicknames. Athletic Director Warren Bovard, son of university president Dr. George Bovard, asked Los Angeles Times sports editor Owen Bird to select an appropriate nickname. Bird said, "At this time, the athletes and coaches of the university were under terrific handicaps. They were facing teams that were bigger and better-equipped, yet they had splendid fighting spirit. The name 'Trojans' fitted them."
The winner of the game keeps a Shillelagh, which is a Gaelic war club made of wood from Ireland, for a year. This Shillelagh has emerald-studded shamrocks representing Notre Dame victories and ruby-adorned Trojan heads standing for USC wins (each is engraved with the year and final score).
In 1952, the Notre Dame Alumni Club of Los Angeles presented the trophy. The original shillelagh was flown in from Ireland by Howard Hughes' pilot. Although the trophy was introduced in 1952, the medallions on the shillelagh go back to 1926.
The original shillelagh ran out of space after in the 1989 game and was retired. It is on permanent display at Notre Dame. The new one is slightly bigger and was commissioned by Jim Gillis, a former baseball player at both schools and one-time president of the Notre Dame club of Los Angeles.
Touchdown Jesus is the famous painting of Jesus on the Hesburgh Library across from the stadium. It can be seen from inside the stadium, and since the painting lies directly behind the south endzone and depicts Christ with his hands uprised, it has become known as "Touchdown Jesus."