Three centuries before christ, the greeks thought that a certain vein called the 'love vein' had started from 'the third finger (excluding the thumb)' and gone all the way to the heart. So to them, putting a ring symbolizing 'the promise of love' on their third finger was quite natural.

Later on the romans accepted this custom along with the greek anatomical(ÇغÎÀÇ) chart. In order to clarify the vagueness(¸ðÈ£ÇÔ) of which finger being the third, they described it as 'the finger next to the little finger. This finger was also named 'the curing finger' by the roman doctors which was used when stirring medicine. It was because they believed that they would be able to sense any poison that might be in the medicine before giving it to the patient, since the vein in the finger was connected directly to the heart.

And the following is how the modern people explain the reason for putting their ring on the ring finger of their left hand. They say that most people are right handed and since the left hand is less active and the ring finger functions the least, it is least likely to lose an expensive jewel or their wedding ring. But it seems that the emotional thinking that the 'love vein' lies within will secure the everlasting love, rather than today's rational thinking that it just 'protects' the ring.