From workaday outerwear to the laps of multi-billionaires, blue jeans have withstood the wear and tear of time as an American icon.

Originally called overalls (even without the straps), the pants evolved from a practical solution to protect the laboring limbs of workers to a style suiting just about every demographic. The garment has fit the thighs of miners, farmhands, cowboys, rebels, hippies, rockers, hip-hop artists, fashionistas and businesspeople alike. Even Apple founder Steve Jobs adopted them, along with a black mock turtleneck, as his signature look.

Heck, you’ve probably worn a pair, too.

So how did a humble Gold Rush-era innovation in trousers come to define a nation? Fortune spoke with Levi Strauss historian and archivist Tracey Panek about the evolution of the attire. With her help and some research of our own, here’s a selection of the most important moments in denim history.