Diamonds are so closely tied to women's jewellery today that it is easy to assume this has always been the case. It genuinely has not. For centuries, diamonds were considered a symbol of male power, worn almost exclusively by kings and noblemen, long before they became associated with women at all.
It started with ancient India

Some of the earliest recorded reverence for diamonds comes from ancient India, where they were viewed through Hindu religious tradition as a symbol of kingly power. Diamonds were worn as talismans specifically by men and were actually forbidden to women in that early context.
European kings claimed them for themselves

That pattern continued into medieval Europe. In the 13th century, France's King Louis IX passed a sumptuary law reserving diamonds specifically for the king, based on how rare and valuable they were considered at the time. Sumptuary laws generally- strict rules dictating who was permitted to wear what- were common across medieval Europe, and jewellery, including diamonds, was frequently used to visibly enforce rank and status among the male aristocracy.
Kings quite literally wore more of them

Henry VIII of England reportedly owned hundreds of rings and brooches, many heavily set with diamonds and pearls, and portraits from this era consistently show kings far more heavily bejewelled than most women of equivalent rank. Under Louis XIV of France, more large diamonds were imported from India than at any other point in history, almost entirely to adorn the king and his male court.
So when did the shift actually happen

The change came gradually, as diamond cutting techniques improved from the 14th century onward, making the stones more brilliant and more widely available beyond royal courts. Over the following centuries, as diamonds became more accessible to the wealthier merchant classes and eventually connected to romance through the rise of the engagement ring, the association slowly shifted toward women, eventually becoming the dominant cultural narrative we know today.
Why this history is worth knowing

Men wearing diamonds is not a new trend or a modern style statement; it is genuinely a return to where the stone started. The current rise in men's diamond jewellery is less a departure from tradition and more a homecoming.
If you are curious what a diamond looks like on you, visit Azzallure. Diamonds were made for exactly this, long before they were ever considered anyone else's.