The concept of brands and brand marketing have evolved over decades. Traditionally, consumers were familiar with only a few products that were available in the market. Beginning from the 1870s a number of companies began pushing 'branded products,' which familiarized consumers with more brands. From 1915 through the 1920s, manufacturer brands were established and developed further, which increased companies' reliance on brand advertising and marketing. However, the Great Depression led to a severe drawback in brand progress, as companies were left with few ways to increase revenue and get their business back on track. For the sake of their brand and survival in a hopeless market, companies such as Procter and Gamble, General Foods and Unilever developed the discipline of brand management. The "brand manager system" refers to the type of organizational structure in which brands or products are assigned to managers who are responsible for their performance.