Engagement rings have existed for thousands of years. The ancient Egyptians gave silver or gold rings to their loved ones and these were worn on the third finger of the left hand as was discovered in many ancient Egyptian tombs; the Romans also gave them, either made of silver, gold or iron with some rings having a small key attached. However the custom disappeared sometime in the Dark Ages. It was only revived in Europe in the 13th century, two hundred years before the Archduke Maximilian set the trend for adding a diamond to the engagement ring.
The modern Western practice of giving or exchanging a diamond engagement ring is traditionally thought to have begun in 1477 when Archduke Maximilian I of Austria, gave his beloved Mary of Burgundy a diamond ring as an engagement present. Diamonds were extremely rare and expensive at the time. The practice of giving a diamond ring was limited to royals and certain nobles until the mid mid 1800s following this event.
It took a discovery in South Africa to turn diamonds into a commercially mined product and therefore a more common feature for the engagement ring. In 1866 a boy named Erasmus Jacobs found a unique shiny looking stone lodged on the banks of the Orange River in South Africa. He began using the stone in games until his parents realized it may have value and it was eventually sold numerous times before being discovered as a diamond. Due to the circumstances of the discovery of this diamond, it became popularly known as the Eureka diamond. Less than a decade later in South Africa, in 1871 an 83.5 carat stone was found on property belonging to the De Beers brothers by a cook working for a prospecting party marking the discovery of the Kimberley diamond deposits; the largest in the world. This was the first leap in The De Beers being responsible for the broader commercialization of the diamond engagement ring.
The De Beers Company was the sole owner and operator of these newly discovered mines in South Africa and the company maintains a near monopoly over diamond supply to this day. During the Great Depression as demand for diamond rings slumped heavily, the De Beers Company began an aggressive marketing campaign led by the firm N.W Ayer & Son involving photographs of glamorous movie stars covered in diamonds. This is said to have resulted in a 50% increase in diamond engagement ring sales over three years. They added to this marketing success with the launch of the classic slogan “A Diamond is Forever.” in 1947 which has been eternally successful and even inspired the title of James Bond film.
Clever marketing campaigns throughout the 20th century by the likes of De Beers and Tiffany Co together with limited supply and the enduring qualities of the diamond have since then made the diamond ring synonymous with the engagement,