Karkaroff and DE question

[Hagrid]

No: HPFGUIDX 137515

The Death Eaters are a group supporting an English Dark Wizard. So 
what is a Bulgarian doing in the Death Eaters?

If he was the headmaster of an ancient wizarding school, reknown for 
it's Dark Arts, then I immagine he is MUCH older than Snape and maybe 
older than Riddle too.

So does anyone know when he joined LV?

Was it overseas?

If he was in Drumstrang when he met LV, could a Horcrux be hiding 
there?
-aussie-