- Doesn't use database. Databases complicate installation and backup procedures.
- Doesn't create any own metadata, on the other hand uses filesystem metadata to the maximum extent.
- "Keep it simple, stupid," both on source and user level.
- Include only basic features, everything else should be implemented in plugins.
- Keep LionWiki usable from just one file.
LionWiki was created as a fork from french-only WiKiss 0.3 which is itself fork from TigerWiki (hence the name) which is again fork of roWiki. There are many forks and descendants of roWiki, there is awesome graph of its evolution - download here or local copy here.
Oldest LionWiki ascendant is roWiki, small 9KB script (in its latest version) which supported wiki markup, recent changes and history. roWiki author is Marc Rohlfing firstname.lastname@example.org . Project is now dead and original website inaccessible (archived here). If you would like to see roWiki, you can download it from here (version 1.05, latest version known to me).
TigerWiki is fork (or successor) of roWiki. It's probably the most known software of these four "relatives" and is still used on many websites. Its website used to be on chabel.org, but this domain is now unregistered. Apparently, there used to be several language branches - English, French and German. Latest version is probably 2.22 (some websites report this version) but I couldn't find it anywhere. So, if you are interested, you can download version 2.21 EN from here.
WiKiss is again fork (or successor) of TigerWiki written by JJL, probably French branch as it is completely in French language (even source code comments and variable names). Its current version is 0.3 released sometimes in 2007. Its status is unknown, probably dead now. Website is at http://wikiss.tuxfamily.org/
WiKissMe is a derivative of WiKiss, a modified version, that's why the Me in the end, also influenced a little by TigerWiki. Developed by Neven Boyanov and friends. WiKissMe is a wiki content management system that stores its data in flat text file. It is written in PHP 5. It has flexible plugins and modules architecture featuring blog, comments, captcha and others. Supports themes with templates as well. Website is http://www.wikissme.org/ hosted at SourceForge (http://sourceforge.net/projects/wikissme).