The Gender Plague was a mysterious magical plague that struck suddenly all over the known world almost two-thousand years ago. It’s name comes from the fact that it killed more than five times as many men as it did women.
Those who hadn’t reached puberty were more resistant to the disease, but even then it killed twice as many boys as girls.
No cure was found for the plague. It disappeared as quickly as it appeared and has not been seen since.
The results of the plague have lasted a long time. Magic was already a great equalizer in gender relations, but with the loss, in some cases, of the entire recognized ruling line of various kingdoms, women were needed to hold power.
Another long term effect was the tradition of women taking their mother’s last name. Marriages tend to result in a combination of last names, rather than the woman changing her last name to that of her husband’s.
Most objections to the idea of women holding business or political power were silenced through a combination of those having the most objections dying and the fact that civilization didn’t collapse as a result.