[Edi]

The Ancient Master also trains all the units of the commander who enters it and at 8 XP per turn, the first one or two stars rack up pretty quickly, which can be good for some things, especially if the province is in a staging area. Adding a Champion's Skull to a commander who enters the site will cause that commander to hit 12 XP per turn, which is a pretty good clip and may prolong staying in the HoF in some instances if he had made it there already.