>>49689649
>- Oldest known Touhou arrange (there are some ideas, like this https://web.archive.org/web/20011117221337/http://www16.big.or.jp/~zun/html/music.html, made in 2001)
Should ZUN's own stuff count? If not, it's probably the album Prizm Light Fragments, and early stuff by Colorful Cube in general, at least that's the common belief