Back in the Classical era it was believed that there was a vein that ran directly from the heart to the fourth finger of the left hand. This vein was called "vena amoris" in Latin, which literally means "vein of love". This theory has been cited in western cultures as one of the reasons why the engagement/wedding rings are placed on the fourth finger of the left hand.
The tradition of engagement rings as we currently know it arose in the medieval era, when, in 1215, Pope Innocent III instituted a mandatory waiting period from engagement to marriage . For the first few hundred years in the tradition of engagement rings, only the wealthiest nobles could afford rings set with precious stones, and most engagement rings were simple metal bands .
In the modern days, buying engagement rings with precious stones is no longer a privilege of the nobles. Engagement rings became highly symbolic with many including sets of stones with personal meaning. One popular model features the birth stones of the engaged couple and each of their parents. The Victorian tradition of engagement rings included precious stones whose initials spelled out a message. A common example is when the engagement ring is set with Lapis lazuli, Opal, Vermarine, and Emerald to spell out the word LOVE.
In modern day England and the United States, among other countries, the most common type of engagement ring is a diamond solitaire . This tradition of engagement rings is largely due to an advertising campaign by De Beers in the 1940s. In some countries, such as France, other precious stones are commonly seen in engagement rings . One tradition of engagement rings calls for the ring to be expensive as a symbol of the man's commitment.