The business suit was invented to make class invisible and rank visible.
The modern business suit traces its origins to Beau Brummell, a British dandy who, in the early nineteenth century, popularized a restrained style of men's dress built on dark colors, clean lines, and precise tailoring.1 Brummell's influence replaced the aristocratic excess of the eighteenth century with a uniform that signaled respectability through simplicity.
By the mid-nineteenth century, as the modern office emerged, the dark suit became the standard uniform of professional work. It required no explicit mandate. The dress code was enforced through imitation and social pressure.
The phrase "dress code" itself appeared in English in the mid-twentieth century, formalizing what had previously been understood as custom.2 Corporate dress codes proliferated in the postwar decades, specifying not just the suit but the color of the shirt, the width of the tie, and the acceptability of patterns.
IBM under Thomas Watson Sr. became synonymous with the corporate dress code. The company's sales force was expected to wear dark suits, white shirts, and conservative ties, a uniform so consistent that "IBM blue" became a phrase.3
Casual Friday, introduced widely in the 1990s, represented the first formal loosening. Technology companies, led by Silicon Valley, abandoned the suit entirely. Mark Zuckerberg's gray t-shirt and Steve Jobs's black turtleneck became counter-uniforms, dress codes that signaled a rejection of the old code while imposing new expectations of their own.4
The dress code was always a signal, not of what you did, but of where you belonged in the hierarchy of who gets taken seriously.