Doug Engelbart, the man responsible for a number of key inventions during the early age of computing, has died at the age of 88. News of his death was confirmed by the Computer History Museum as well as the Stanford Research Institute according to multiple reports.

Engelbart was described as a visionary during the 1950s and ‘60s when a single computer enveloped an entire room. He believed that computers could be used to augment human intellect and share ideas about solving various world problems. True enough, we have the Internet today but it was another idea – or invention, rather, that was Engelbart’s most successful accomplishment.

The American inventor is responsible for creating the mouse which he first developed in the 1960s and patented in 1970. Early prototypes consisted of a wooden shell with two metal balls inside: one for the X axis and one for the Y axis.

As you can imagine, a device of this nature was well ahead of its time but perhaps nobody ultimately realized that more than Engelbart himself. You see, the mouse didn’t become commercially available until Apple’s new Macintosh hit the scene in 1984. By 1987, however, the patent on his device expired and landed in the public domain.

This meant that Engelbart and his colleagues weren’t able to collect royalties on the mouse once it became widely used. To give you a bit of perspective, more than 1 billion mice have been sold since the mid 1980s.