Upon Dracula's defeat at the hands of Jonathan & Charlotte, he yells "One day my powers will be fully revived!" or something like that, pretty much referring to his imminent return in 1999~
1897 is 100 years after 1797(SotN), so Dracula could have been at full power, but we'll never know for sure since a "Bram Stoker's Castlevania" game will likely take a lot of liberties & "do it's own thing" from the novel, so to speak (side not, he was prematurely resurrected by I Forget His Name in OoE, but the game never confirms the exact year). The PoR Timeline Bonus has an entry for 1897, which says "Quincy Morris, Belmont descendant, keeps Dracula at bay." They could've put "1897-Bram Stoker's Dracula" and left it at that, or "1897-Quincy Morris along with Jonathan Harker & Van Helsing go on a quest to rescue yaddayadda." Instead, they left it somewhat ambiguous.