Using diamonds in engagement rings goes back to the Middle Ages and Romans. The diamond rings worn by Romans that were inset with diamonds did not necessarily designate an engagement, but were worn due to the supposed supernatural powers of a diamond. Diamond engagement rings became very popular during the twentieth century, in large part due to the marketing strategies that De Beers used.

During the Middle Ages, diamonds were valued for their mystical powers, rather than for their beauty. The Romans believed that diamonds had the power to prevent poison from taking effect, ward off insanity and could even banish fears of vanity. Diamonds were even said to ward off evil and encourage good luck to fall upon the wearer. Italians in the Middle Ages took it a step further stating that a diamond ring could maintain the agreement between couples. Because of this reasoning, they recommended that diamonds be used in wedding and engagement rings.

During the twentieth century diamonds became increasingly popular in engagement rings. The popular jewelry retailer, De Beers, made considerable campaigns depicting diamonds as last forever. "A Diamond is Forever" is a popular and well-known slogan that is directly linked to their campaign ventures. Due to the marketing and popularity of engagement rings, the use of diamonds has become very popular and the value placed on diamonds is now due to the beauty and cut of the gem.

During the Middle Ages, Romans were known to wear diamond rings for supernatural purposes because of the supposed mystical attributes that were associated with diamonds. Diamonds were not considered to be beautiful until the twentieth century marketing campaigns that De Beers made in promoting diamonds for engagement rings. Now, engagement rings traditionally have a single diamond that varies in size from ring to ring. The value of diamonds has changed drastically since they have been worn by Romans. They went from being valued because of their supernatural abilities, to being valuable based on their beauty alone.