Sir Clive Sinclair, the inventor of the world’s first slimline pocket calculator and founder of Sinclair Research, has died. He was 81.

Sinclair’s death was due to succumbing to a long illness; he died in his home. The entrepreneur and his company released the ZX80 home computer back in 1980 and was a really popular machine due to its build-it-yourself kit marketing, capabilities, and its £100 price tag.

Most importantly, Sinclair and his company invented the ZX Spectrum, which became the best-selling personal computer in the UK. Rest in peace, Sinclair.