Yukihiro Matsumoto

Matsumoto, generally known as Matz, released Ruby in 1995. He wanted a scripting language that was thoroughly object-oriented — where even integers are objects — and that borrowed expressiveness from Smalltalk and Perl without inheriting their respective awkwardnesses. The principle of least surprise, that the language should behave as you would guess, recurs in his descriptions.

The language was virtually unknown outside Japan for ten years. The breakthrough came in 2004 with Ruby on Rails, which made web development considerably faster and influenced a whole generation of frameworks in other languages. Matz still leads development, with performance work the main thread in recent versions.