That is for newer versions; I found an older download for 1.7.10 which notes that it is now "SanLib". I couldn't find any CurseForge pages for older versions, but did find the original forum thread, which is fortunately still up (many old threads, and mod downloads, were lost a few years back due to EU GDPR regulations and most old users no longer being active so they never gave their consent. It is still possible to find downloads on mod repost sites but I wouldn't trust them) and has a spoiler at the bottom with links to downloads for older versions; I checked the link for 1.5.1 (CSM_v911) and the download still works (you'll have to go through an ad site; here is the GitHub where the files are hosted, including Manager Pack, although I'm not sure which version is required for 1.5.1).
For Minecraft version 1.5.1, the GitHub link TheMasterCaver posted can help.
The video above is an installation video for exactly what you need (however, it's outdated, as you would expect for such an old version) From what I've found looking through the video, version 1.4.1 (or v141) seems to be for 1.5.1. It's likely other versions of the Manager Pack can work with 1.5.1, such as v1.4.2, however it's your choice on what version you choose
So i need the 1.5.1 version of the SanAndreasP's Manager Pack for the clay soldiers mod, where can i find it?
There isn't one. It only goes back to 1.10.2.
https://www.curseforge.com/minecraft/mc-mods/sanlib
"We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far."
That is for newer versions; I found an older download for 1.7.10 which notes that it is now "SanLib". I couldn't find any CurseForge pages for older versions, but did find the original forum thread, which is fortunately still up (many old threads, and mod downloads, were lost a few years back due to EU GDPR regulations and most old users no longer being active so they never gave their consent. It is still possible to find downloads on mod repost sites but I wouldn't trust them) and has a spoiler at the bottom with links to downloads for older versions; I checked the link for 1.5.1 (CSM_v911) and the download still works (you'll have to go through an ad site; here is the GitHub where the files are hosted, including Manager Pack, although I'm not sure which version is required for 1.5.1).
TheMasterCaver's First World - possibly the most caved-out world in Minecraft history - includes world download.
TheMasterCaver's World - my own version of Minecraft largely based on my views of how the game should have evolved since 1.6.4.
Why do I still play in 1.6.4?
For Minecraft version 1.5.1, the GitHub link TheMasterCaver posted can help.
The video above is an installation video for exactly what you need (however, it's outdated, as you would expect for such an old version) From what I've found looking through the video, version 1.4.1 (or v141) seems to be for 1.5.1. It's likely other versions of the Manager Pack can work with 1.5.1, such as v1.4.2, however it's your choice on what version you choose