On Thursday, a van careened into pedestrians along Las Ramblas in Barcelona, killing 13 and injuring at least 100 in a terror attack for which ISIS later claimed responsibility. (The degree to which the group communicated with attackers beforehand, if at all, remains to be seen.) It was the deadliest such incident in Spain since the 2004 Madrid train bombings that killed nearly 200 people, and world leaders responded with a wave of solidarity and sympathy. Initially, U.S. President Donald Trump seemed to join in.

“The United States condemns the terror attack in Barcelona, Spain, and will do whatever is necessary to help,” he tweeted, shortly after. Later, he added “Be tough & strong, we love you!”

Within 45 minutes, the president had changed his tone, directing followers to Google the work of early 20th Century U.S. General John Pershing.

Presumably, Trump meant to direct readers to the claim that in 1911, during the Spanish-American War, Pershing had put down a Muslim insurgency in the Philippines by forcing a group six rebels to watch them kill six of their comrades, using bullets dipped in pig fat, then wrapped their corpses in pigskin and entrails—a desecration, given that pork products are forbidden in Islam. Trump’s own version of the tale, which he told often on the campaign trail, inflated the number to 49 Muslims being killed with “bullets dipped in pigs’ blood,” and one lone survivor left to warn his people.

According to Snopes, the urban legend fact-checking service, any version of the story is false. Snopes found no reference to the incident in any of Pershing’s biographies. Furthermore, it could not find evidence that he executed any Muslims or Moros during this rebellion. Instead, Pershing made a specific effort to prevent them from taking radical action: rather than storming the sacred mountain where they had hoped to make a last stand, he simply surrounded the hill and cut off their supplies. “The fact is that they were completely surprised at the prompt and decisive action of the troops in cutting off supplies and preventing escape,” he wrote in his official report of the battle, per Snopes, “and they were chagrined and disappointed in that they were not encouraged to die the death of Mohammedan fanatics.”

As Americans have learned in recent months, though, facts do not particularly matter to Donald Trump. Nor does consistency: when he first told the story in 2016, he claimed that Pershing’s actions ended “radical Islamic terrorism” for a mere 25 years, not 35, and Trump did not retract the story after it had been repeatedly proven false. Politifact also reported that the rest of Trump’s premise is untrue: the region was still wracked with instability long after Pershing fought there, the Moros rebels were not simply motivated by religion, and that defiling Muslims’ bodies with pig parts had any deterrent effect. Not that the relative truths of a given historical argument have ever stopped Trump from making a hasty pronouncement for a call to arms.