Public relations (PR) is the process of maintaining a favorable image and building beneficial relationships between an organization and the public communities, groups, and people it serves. Unlike advertising, which tries to create favorable impressions through paid messages, public relations does not pay for attention and publicity. Instead, PR strives to earn a favorable image by drawing attention to newsworthy and attention-worthy activities of the organization and its customers. For this reason, PR is often referred to as “free advertising.”
In fact, PR is not a costless form of promotion. It requires salaries to be paid to people who oversee and execute PR strategy. It also involves expenses associated with events, sponsorships and other PR-related activities.
Marketing -- possibly called sales -- was the more dominant function.
Public relations was of secondary importance and was probably done to support and enhance marketing efforts.
If it was a small company, it might not have had a separate and identifiable public relations unit at all, or it might have had a public relations person or unit which provided subsidiary support from within the marketing department.
If it was a medium to large corporation, it probably had separate marketing and public relations departments. Which of them was larger and more influential within the company was almost as likely to be the result of the organization's unique evolution, including its internal politics and staff personalities, as a conscious business decision.