Traditionally, character's under Unix were encoded in a locale-specific manner: ISO 8859-1 in Western Europe, ISO 8859-2 in Eastern Europe, EUC-JP in Japan, etc. In the 1990s, there was a major push to get XFree86 (the ancestor of X.Org) to switch to locale-independent UTF-8, lead mainly by Markus Kuhn and Bruno Haible.
The link is to Markus Kuhn's web page, which appears to describe the UTF_8 software available around 1998 or so.
You can render it pretty well, not perfect, but good enough to actually read it, as opposed to not being able to render it at all or rendering mojibake à la Кракозябры instead.