May 2, 1983 — Microsoft Released the Two-Button Mouse

The original mouse, patented by Douglas Engelbart, had only one button. Later, in the 1970s, Xerox built a two-button mouse for its Xerox PARC computer. But the Xerox PARC machine never became a mass-market product, and the mouse itself was not sold commercially.

In 1983, Microsoft released the first widely available two-button mouse. After that, two-button mice became standard. Over time, mice gained scroll wheels, extra buttons, and indicator lights, but the two-button mouse remains the classic image of this device.