When Franklin D. Roosevelt was inaugurated on March 4, 1933, the United States was entering the fourth year of the Great Depression, the worst economic downturn in the nation’s history.

The stock market had fallen a staggering 75 percent from 1929 levels, and one in every four workers was unemployed. In the weeks before Roosevelt took office, things had gotten even worse. Some 4,000 banks were forced out of business, costing millions of people their life savings. As depositors panicked and rushed to withdraw their money from the remaining banks, the crisis threatened to bring down the nation’s entire financial system.

“The only thing we have to fear is fear itself,” Roosevelt famously declared on that cold and cloudy Inauguration Day. But stirring words would not be enough, and Roosevelt knew it: “This nation asks for action, and action now.”

Two days later, he declared a nationwide “bank holiday,” temporarily shutting down the nation’s entire banking system. Called into a special session, Congress passed the Emergency Banking Act on March 9. The bill gave the federal government the power to investigate each bank’s finances. Those that were judged to be healthy and stable enough would reopen on March 13.

But on March 12, 1933, the day before banks were set to reopen, it wasn’t clear that these emergency measures had done enough to calm the public’s fears. That evening, at 10 pm Eastern time, Roosevelt addressed the nation via radio broadcast, directly from the Diplomatic Reception Room at the White House. (Yes, he was actually sitting next to a fireplace.)

“My friends, I want to talk for a few minutes with the people of the United States about banking,” he began. For roughly 13 minutes, more than 60 million Americans listened as Roosevelt explained—in straightforward language designed “for the benefit of the average citizen”—what the federal government had done in the past few days to address the banking crisis, why they had done it and what the next steps were going to be.

After explaining how banking worked, Roosevelt laid out what had happened to cause the current crisis. He argued that the government’s emergency measures would enable a survey of the nation’s banks and allow stable ones to reopen. After that, he said, people could feel completely safe returning their money to the banks rather than hoarding it at home out of fear. “I can assure you,” he said, “that it is safer to keep your money in a reopened bank than under the mattress.”

Finally, Roosevelt called on the American people to renew their “confidence and courage,” and to have “faith,” rather than be “stampeded by rumors or guesses.”

“Let us unite in banishing fear,” he concluded. “Together we cannot fail.”

Roosevelt wasn’t the first president to use the medium of radio, but he was the first to use it so effectively to speak directly to the American people, without the filter of the press. Using a slow, calm and steady voice that rose and fell naturally, he seemed to be engaging in a conversation with his listeners. In reality, his words had been carefully written, revised and fact-checked by a team of advisers, but Roosevelt had a way of making them feel informal and fresh.

The effect was powerful: On March 13, when healthy banks reopened, people lined up in droves to return their cash. More than half of the funds Americans had withdrawn during the crisis were back in the bank within two weeks. March 15, the first day stocks were traded after the banking holiday, saw the market’s largest ever one-day percentage price increase, reflecting a new surge of confidence among American investors.

Before Roosevelt’s second radio address, broadcast on May 7, 1933, the CBS station manager Harold Butcher dubbed the speeches “fireside chats.” Thousands of letters had begun pouring into the Roosevelt White House every day, many of them expressing gratitude for the president’s words. A single fireside chat could generate more than 450,000 cards, letters and telegrams.

It was a long, hard slog, however, before the country began to regain its economic foothold. After a period of gradual recovery, a sharp recession hit in 1937. Then a second severe contraction in 1938 reversed many gains in production and employment and prolonged the effects of the Great Depression through the end of the decade. Through it all, FDR continued to speak to the American people directly through his radio addresses.

Roosevelt went on to deliver around 30 fireside chats over the course of his long presidency, as the nation took on economic recovery, only to be thrust headlong into World War II. The fireside chats enabled Roosevelt to connect with Americans in an unprecedented way—an ability that likely contributed to his historic four presidential victories.