I think it's entirely possible that Lucas/Lucasfilm/licensed content creators gave that question no thought at all before they started making the prequels/all their related stuff. A lot of people here seem to like the idea that there was some pure version of every single thing laid out before George started making the prequels and then he changed a bunch of stuff from what it was originally supposed to be, but for something as small as this, I honestly think it's more likely that no one thought it was that important for a while and it went unaddressed until those movies with Obi-Wan Kenobi as a young man started coming out. Granted, I have no idea if it actually is explained in any of the EU stuff from that era either. I just think that the prequel bullshit that you want to avoid is probably the only place an answer exists at all.