Definition

I decided to pull up some definitions of 'Advertisement' and came up with these from the Encyclopedia.

Advertising is a form of communication that typically attempts to persuade potential customers to purchase or to consume more of a particular brand of product or service. Many advertisements are designed to generate increased consumption of those products and services through the creation and reinforcement of "brand image" and "brand loyalty".

Egyptians used papyrus to create sales messages and wall posters. Commercial messages and political campaign displays have been found in the ruins of Pompei and ancient Arabia. lost-and-found advertising on papyrus was common in Ancient Greece and Ancient Rome. Wall or rock painting for commercial advertising is another manifestation of an ancient advertising form, which is present to this day in many parts of Asia, Africa, and South America.

In June 1836, French newspaper La Presse is the first to include paid advertising in its pages, allowing it to lower its price, extend its readership and increase its profitability.

At the turn of the century, there were few career choices for women in business; however, advertising was one of the few. Since women were responsible for most of the purchasing done in their household, advertisers and agencies recognized the value of women's insight during the creative process. In fact, the first American advertising to use a sexual sell was created by a woman – for a soap product. Although tame by today's standards, the advertisement featured a couple with the message "The skin you love to touch".

In the early 1920s, the first radio stations were established by radio equipment manufacturers and retailers who offered programs in order to sell more radios to consumers. When the practice of sponsoring programs was popularised, each individual radio program was usually sponsored by a single business in exchange for a brief mention of the business' name at the beginning and end of the sponsored shows. However, radio station owners soon realised they could earn more money by selling sponsorship rights in small time allocations to multiple businesses throughout their radio station's broadcasts, rather than selling the sponsorship rights to single businesses per show.

The late 1980s and early 1990s saw the introduction of cable television and particularly MTV. Pioneering the concept of the music video, MTV ushered in a new type of advertising: the consumer tunes in for the advertising message, rather than it being a by-product or afterthought.

Another good resource to read would be the Wikipedia on Advertising.

Some examples of early Print Advertising.