It’s Feb. 29, a day that comes around only once every four years. In the early 20th century, Leap Year meant more than an additional day on the calendar: It became a chance for women to propose marriage to men — at any point during the year, not just on Feb. 29.

The tradition’s roots are uncertain, though historian Katherine Parkin of Monmouth University says it may have originated in Irish or Scottish folklore. By 1908, there were Leap Year postcards like the ones pictured here, portraying husband-hunting women as threatening, masculine and violent. The men, on the other hand, look scared, small and emasculated.

“The images clearly convey the ugliness and desperateness of these women,” says Parkin, who maintains a database of Leap Year postcards from 1904 to 1920.

Leap Year had the potential to disrupt traditional gender roles, Parkin says, but instead had the effect of entrenching them. The postcards, she notes, use humor and shame to ridicule women who might dare to take control of their romantic fates. She’s found some evidence, she says, of women proposing marriage to men in the early 1900s. But the tradition never took off.

“Instead of transforming it into an accepted practice, the popular culture mocked and belittled women’s proposals,” Parkin wrote in a 2011 article on Leap Year marriage proposals. “Scorned and ridiculed for trespassing against male privilege, along with those who wore pants or participated in politics, female proposers learned that seeking rights threatened those who held power. In the end, the leap year custom helped ensure that men continued to hold the power in matters of matrimony.”

A century later, Parkin doesn’t think much has changed. There’s still “a real suspicion” of women who propose marriage to men, she said in a phone interview, adding that she thinks marriage proposals have become more traditional, not less. In another example of traditionalism, the proportion of grooms asking their in-laws for permission to marry has increased in recent years. And we’re still uncomfortable with women earning more than their partners, Parkin notes. The discomfort with women-initiated proposals could be part of that, since the proposal is a way of saying: I will provide for you.

In 38 percent of heterosexual marriages, the woman makes more than the man. Until we get used to that economic dynamic, our ideas of romantic proposals might remain stuck in the past.

In the meantime, we have celebrity proposals such as Pink’s and Jennifer Hudson’s to remind us that a woman need not wait for a man to get down on bended knee.