Why did pop art start?

Pop art began as a means of subversion of fine and classical art. By including modern images, it acknowledges how pervasive images from pop culture can be.

Rather than being a commentary or criticism of pop culture or consumerism, pop art merely includes images from advertising, marketing and several other forms of entertainment as a means of celebrating and acknowledging their far reach in society. Though the pop art movement began in London in the 1950s, a large following picked up momentum in the 1960s in the United States. It is largely considered the precursor to the post modern art movement