Final answer:
Archduke Maximilian of Austria presented Mary, Duchess of Burgundy, with a diamond engagement ring, marking the beginning of the tradition of diamond engagement rings in 1477.
Step-by-step explanation:
The historical figure who presented Mary, Duchess of Burgundy, with a diamond engagement ring was Archduke Maximilian of Austria. This act is often cited as the origin of the modern tradition of diamond engagement rings, although the engagement took place in 1477. Rings and jewelry played a significant role in symbolizing alliances and displaying wealth and status among European nobility during that time.