For decades, countless children have arrived on doorstops on October 31 to solicit candy. But many have also toted around a small orange box to collect monetary donations for UNICEF, the United Nations Children’s Fund, which supports international humanitarian efforts. At first glance, those two objectives seem to be at cross-purposes: Halloween is a time for hoarding sweets, not promoting charitable causes. So how did it get started?

According to The New York Times, the tradition began in 1950 with a Presbyterian minister in Pennsylvania named Clyde Allison and his wife, Mary. The couple perceived a stark contrast between kids in the U.S. collecting a bounty of candy and the child refugees who were struggling following the end of World War II. Trick-or-treating seemed like something that could be co-opted to provide assistance.

Allison had a platform to reach kids thanks to his responsibilities overseeing the Presbyterian Church’s nationwide Sunday school program. A few years prior, the Allisons had encouraged neighborhood kids to collect shoes so they could be repaired and sent to refugee camps. Kids also collected soap and coats. The venture was successful enough that no more shoes were needed, and in 1950 the Allisons turned their attention to UNICEF, which had begun charitable fundraising in 1946. With the blessing of First Lady and UNICEF advocate Eleanor Roosevelt, the Allisons wrangled kids to collect money for the group in 1950.

Kids marched through their towns grabbing candy: They also toted empty milk containers covered in orange paper to collect loose change. According to Monroe Allison, the couples’ son, Eleanor phoned afterward to tell the Allisons that the effort had raised more money for UNICEF than any single fundraiser had up to that point—as much as $100,000.

The charitable act also had an unintended consequence: It helped normalize trick-or-treating, which some adults were still wary of. Some viewed it as a kind of pint-sized extortion. UNICEF helped quell that opinion, as did depictions of trick-or-treating in the Peanuts comic strip and Donald Duck cartoons.

UNICEF still promotes an annual program, though more recently they’ve encouraged kids using a QR code for homeowners to scan rather than cash donations. Proceeds are used to fund vaccination campaigns, education, and clean water in underprivileged areas.

As of 2022, UNICEF estimates trick-or-treaters have raised $195 million over the years, with the organization helping to vaccinate roughly half of all children under age 5 in a given year.

This article was originally published on www.mentalfloss.com as How UNICEF Transformed Halloween Trick-or-Treating.