The origin of GOP goes all the way back to 1850s and is the short form for 'Gallant Old Party'. It was the traditional name for the Republican Party of the United States.
The first convention of the party was held in 1854 and the abbreviation was formed by the 1870s. The anti-slavery activists found a common ground and fought for 'free soil, free labor, free speech, free men'.
In 1860, Abraham Lincoln became the President and thus the Grand Old Party became one of the major political players of America.
The first official reference to GOP was made in a Congressional Record in 1875, as 'the Gallant Old Party' was found. After about a year, according to Harper's Weekly, the expression 'Grand Old Party' was used in Cincinnati Commercial.
The acronym GOP came into existence when 'Boston Post' published an article with the headline 'The G.O.P Doomed', in 1884. This abbreviation was picked up by the New York Herald for their articles. Thus, GOP became a common term to be used for the Grand Old Party or Republican party.
The symbol of the party, the elephant was born out of a cartoon that appeared in Harper's Weekly on November 7, 1874 and before that in 1860 an issue of Railsplitter and another cartoon in 1872 published in Harper's Weekly, related the elephant to the Republican party.
The elephant became symbol of the party with the cartoon made by cartoonist Thomas Nast, with the Harper's Weekly. The cartoon depicted a donkey representing the Herald, wearing a lion's skin trying to frighten away animals in the forest.
One of the foolish animals was an elephant that represented Republican votes. It did not mean the party and after the elections in which the Republicans fared badly, Nast came up with another cartoon that illustrated the elephant was trapped, that is, the Republican vote has been tempted away from its favorite allegiance.
Soon the elephant was adopted by other cartoonist which became a symbol of the party, not the votes. The donkey that frightened the elephant soon became a representation of the Democratic party from the initial representation of the Herald.
Around the same time, with the invention of automobiles, the term GOP was also used for 'get out and pushed'. This term became a good slogan for the Republicans who believed in making thousands of hardworking Americans to get out and push them to support the causes of the Republican Party.
During the presidential elections in 1964, the term 'Go-Party' was used and Nixon administration referred to it as the 'generation of peace'. The term 'grand old party' came back into use after the speech by President Nixon at the Eisenhower Republican Center in Washington, D.C.
The term Republican was used in place of the traditional name, Gallant Old Party in the 1850s as the founding members wanted to pay homage to Thomas Jefferson.
Thomas Jefferson had used the term Democrats-Republican for his party and the supporters of Jefferson wanted to use the term Republican as their party name, which would echo the Republican values of civic virtue and resistance to corruption and aristocracy.