Hello everybody!

Let's hope the magic works and you can help me find this old game.
- It was an adventure game, I played it on a PC in the late 90's.
- It began with a cinematic showing a young girl being forced to abandon her newborn baby in a forest. Maybe she was a princess, I think there was a castle. Luckily, the baby was found by a centaur (!), who raised him as his own son. Many years later, the boy is a man who begins a journey in search of adventure (or maybe just his origin).
- There were definately English voiceovers.
- There was a map showing several locations. One of them was the Hydra's swamp.
- One of the first things I could do was trading a random old woman on a crossroads one gem in exchange of an elixir -no idea what it did.
That's everything I can remember. I've been looking for this game for years and I now I have decided I could use a little help.
Thanks in advance!