It’s an image that many remember of America’s agrarian past: Kids toiling away on family farms during the long, hot summer break between school years.

So it’s perhaps unsurprising that the origin of the school calendar is often linked to these images — by policy makers and in the media.

In a story about achievement gaps caused by summer vacation, Time Magazine called the school calendar “a legacy of the farm economy.” In a segment on summer programs for low-income kids, NPR reported that the school year was based on an “agrarian calendar that dates back to farm cycles and harvests.” While advocating that kids spend more time in school, Secretary of Education Arne Duncan told The New York Times that the long summer break was “based on the agrarian economy.”

But while there may be a kernel of truth to this theory, it’s mostly wrong.

“What school on the agrarian calendar actually looked like was a short winter term and a short summer term” said Kenneth Gold, a historian at the College of Staten Island. “And if you think about farming needs, that’s actually what makes sense.”

Kids in rural, agricultural areas were most needed in the spring, when most crops had to be planted, and in the fall, when crops were harvested and sold. Historically, many attended school in the summer when there was comparatively less need for them on the farm.

“The whole idea of an agrarian calendar makes it sound like it was an unthinking decision but the current school year was really a conscious creation,” said Gold, who is the author of “School’s In: The History of Summer Education in American Public Schools.”

Urban schools had a very different school schedule, but also included summer. School was essentially open year round, but was not mandatory, and children came when they could. In 1842, New York City schools were open 248 days a year, dramatically more than the 180 or so that they are open today.

In the days before air conditioning, schools and entire cities could be sweltering places during the hot summer months. Wealthy and eventually middle-class urbanites also usually made plans to flee the city’s heat, making those months the logical time in cities to suspend school.

By the late 19th century, school reformers started pushing for standardization of the school calendar across urban and rural areas. So a compromise was struck that created the modern school calendar.

A long break would give teachers needed time to train and give kids a break. And while summer was the logical time to take off, the cycles of farming had nothing to do with it, Gold said.

And none of the reasons for creating the current school calendar related to student achievement. “The conversations that we’re having today about creating a context for academic achievement just weren’t there.”

But today, researchers are considering that exact question.

Long summer breaks have been shown to cause children, especially lower-income children, to lose ground academically. It’s a phenomenon known as “summer slide,” where students return to school in the fall having lost a full month of learning, on average.

Researchers have studied enriching summer programs, summer school, and even year-round school to combat this summer learning loss. One school district in West Virginia has had a year-round calendar for more than two decades. Watch the video below to learn more.