Great!
Don't worry about your obsession with low notes on the piano: I have the same thing with high notes on the piano ;)
There's a bit of clipping here and there, so you might want to lower the volume of the entire mix a bit next time. Not a huge problem, but it's more pleasant to listen to a piece without the 'crackling' in between. Apart from that, mastering is fine as far as I can tell. The guitar (?) at 00:08 is a bit unexpected though. Perhaps it would've been better to let that blend in more with the rest of the piece, like you did with the piano at 00:20, which was a great implementation.
The piece has very 'grand' feeling to it, perfect for an ancient Roman setting. You don't hear music like this on Newgrounds very often, so I'm glad you decided to write it. I like how it also has a mysterious feel to it, which perfectly fits the 'sanctuary' part. Melodies and harmony are good and go well together, so a job well done there.
The arpeggios played by the piano go on for a bit too long, to be honest. Perhaps you should've alternated it with regular chords instead? That's just me being nitpicky though, so it's not a huge problem :P
All in all, 8/10 and 4/5 ;)
Keep up the good work!