In practice, you tend to need something not too out of date. Just about any distro ships with internationalization support, and the fact is that it takes a lot of RAM to do that. A Pentium 1 may not support enough.
I did an install on a Pentium II a few years ago. I used Debian 2.2. Since I had used it back in the day, it seemed easier than finding something more modern that would work.