The earliest written evidence of lube is from Ancient Greece in 350 B.C., when olive oil was being employed with the use of leather dildos. Since latex condoms were not around at the time, using oil as a lubricant posed less problems back then than it does today. I can see olive oil acting as a perfect moisturizer for a leather toy, which would be much more prone to drying out and cracking than a modern day silicone toy, like the Pure Blue Silicone vibrator, would.
I would equate it with the current use of coconut oil as lube, which is the the newest craze around these parts. I’ve used baby oil with much masturbatory success as well, but remember that neither of these products are safe for use with traditional latex condoms. If you’re going to use oil as lube, be sure to use nitrile or polyurethane condoms, like the FC2 or Trojan BareSkin Non-Latex Supra for safety.