Installed Lubuntu 10.10 from March 2011 mag CD on the P166MMX and updated a the repository list. I am using Firefox 3.6.3 from 2010 so don't get any certificate or encryption warnings.
So a 23 year old system, running a 8 year old OS in 2019 quite happily. USB 2.0 card installed and working fabulously along with 100Mbs Realtech nic.
Lubuntu installation routine picked up the Debian Jessie install, resized the partition to give it somewhere to install to and updated the boot manager to reflect there were two operating systems on the hard drive.
Oh and picked up all the hardware on the system. Well, not quite, the 16.5" lcd TV was giving Xorg greif in Lubuntu and Debian Jessie but quickly sorted by hooking up the trusty HP 19' lcd monitor..
There's a glitch in the matrix.