I think you'll find XeTeX (with XeLaTeX because no sane person uses plain TeX except for package authors of course ;) predates LuaTeX by almost a decade.

(Something I ran into in 2008 when I was writing a multilingual book and heard about LuaTeX, only to find out it was still extremely incomplete and was roadmapped to not be done until 2012. And I couldn't wait 4 years)