Trump is not the only convicted criminal to run for U.S. president. Over a century ago, Eugene Debs ran from his prison cell.

Donald Trump, the presumptive Republican nominee in November’s election, has joined an unusual club: presidential contenders who are also convicted criminals.

Before Trump was found guilty on 34 felony counts of falsifying business records in a historic verdict on Thursday, the most well-known convict seeking the Oval Office had been Eugene Debs, a socialist who conducted his presidential campaign behind bars in 1920.

A fiery labor activist, Debs had established himself as an acclaimed orator before he was imprisoned for publicly expressing anti-war sentiment. While Republican Warren Harding won that year’s election by a landslide, defeating Democrat James Cox, Debs managed to secure nearly 1 million votes from his Atlanta prison cell — which Allison Duerk, director of the Eugene V. Debs Museum in Terre Haute, Indiana, called “remarkable.”

“He couldn’t even use his most powerful tool, which was his voice,” she said, adding that he was permitted to put out a short weekly press release during the campaign season but otherwise relied on others in the Socialist Party to get the word out for him. His supporters wore pins with his photograph and inmate number on them, which read: “Convict No. 9653 for President.”

Historians say there are key differences between Debs and Trump. For starters, Debs was serving what he anticipated would be a 10-year sentence when he ran for president, and Trump may avoid prison time entirely: When he’s sentenced on July 11, he faces penalties that range from a fine to up to four years in prison.

The crimes the two men were accused of, and their responses to the allegations, also differ significantly. Trump pleaded not guilty to his charges, which were related to a hush money payment that his