I have been told to pray Sanctus Holy at serran's altar. I feel like I have already been there, but I can't remember where it is. Does anyone know where this is? Help Please!

sounds like the paladin quest not the bard quest

Okay, that's the Paladin quest, not the Bard's quest. For the Paladin, you pray at the Altar of Serran. It's located near the Gypsy encampment (the old boathouse) on the NW side of Nymph lake. (Interestingly enough, there's another one at the far SW side of the Lost Sea area west of Brimloch Roon.)

Sazerac.

P.S. If it is a bard you have, you're on the wrong quest. You have to find the Scroll of Trickery from the Wizard's Study above the library in the Serpent Temple. -Saz