Tom Riddle's backstory

[blaisezz]

No: HPFGUIDX 68657

Hi everyone!
I was just wondering how exactly Tom Riddle found out his own back 
story. 
In COS he knows he was named after his father and grandfather, knows 
his mother(and therefore himself) was Slytherin's heir and knows that 
his father deserted his mother when he was only a baby.
My question is how?
Given that he was raised in a muggle orphanage, Riddle should have 
been in a very similar situation to Harry when he recieved his 
Hogwarts letter aged 11: i.e. clueless. Harry has gradually learnt 
his own history through the stories of Hagrid and Dumbledore, which 
suggests that Riddle also must have been told his own background by 
someone else.
This gets me on to thinking who this other person is, and how they 
knew so much about Riddle's past in the first place.(for some reason 
I keep on coming back to Dumbledore, as despite his hostility and 
mistrust of Riddle he still knows a lot about him and was present 
durng his schooling) 

Anyway, it's been puzzling me... any thoughts?

Ria

PS. In all probabiliy this has been discussed before, but it didn't 
show up on my search of the archives (Then again, knowing yahoo it 
probably wouldn't!). If it has it would be much appreciated if a 
freindly and knowledgable type could point me in the direction of the 
thread(s!). Thank you