It was Pope Stephan I. who supposedly initiated the engagement ring tradition. He was a strong advocate of the indissolubility of marriage and urged men to gift their future wife a ring as an additional confirmation of their imminent marriage.
During the Roman Antiquity and the middle ages, engagement rings symbolized that a woman’s dowry had been received. At the time, rings were made of iron.
The first known diamond engagement ring was given to Maria of Burgundy in 1477 by her future husband, the archduke Maximilian I. of Habsburg.