In ancient Egypt, wearing perfume wasn't as simple as sprinting scent on pulse points. Those who could afford it would wear wax cones on their heads packed with aromatic flowers, herbs and spices. As the waxy air fresheners melted throughout the day, it released scent (and presumable ruining any good hair days). Tre chic!
Fast way, way forward to 18th-century Europe, and perfume wearing was still a gender-neutral embellishment. Especially in France and most especially in the court of Louis XV, wealthy men and women alike wore perfume. The sweet-smelling elixirs had arrived in Europe in the 14th century and were understandably popular for helping mask the unpleasant odors of the day. In addition to wearing it directly on the skin, aristocrats might tote around perfume balls or potpourri in perforated bags or metallic balls called pomanders. They might also tuck perfumed handkerchiefs in the hollow tops of fashionable walking canes.
So what happened? Why did wearing perfume become a feminine gendered behavior?
Because SCIENCE, as Rachel S. Herz explains in the Neurobiology of Scent and Reward:
By this time, men had also stopped wearing visible makeup, although gender dynamics were more to blame than bacterial shenanigans.
Eau de Cologne had already been invented by Italian perfumers living in Cologne, Germany, in the early 18th century. Technically, eau de cologne designates fragrance with an essential oil concentration of less than 10 percent, far less concentrated than eau de parfum. The more generic term "cologne" arrived in 1814, just in time to designate a dude-specific fragrance. Because heaven forbid a gentleman smell like a lady.