If you do find a disc image, to burn it, you will need to make sure your burning software has an option that makes the disc bootable. Toast used to do this, not sure what exists out there these days.

I’m 95% certain it was snow leopard, because I remember making a special trip to comp usa to get it on release day. I didn’t do that for Lion. I might even have skipped that one entirely. I still have that snow leopard disc, somewhere