Back in April, Donald Trump met with Dalia Grybauskaitė of Lithuania, Kersti Kaljulaid of Estonia and Raimonds Vējonis of Latvia and he immediately shared a criticism with the three leaders.

Trump opened by chastising the Baltic leaders for starting the war in the 1990s that ended with the breakup of the former Yugoslavia.

The Baltic leaders were apparently very confused and it took them “a moment” to realize that Trump was confusing Baltic states with the Balkans, according to French newspaper Le Monde.

In today’s ⁦@lemondefr⁩: When #Trump received the leaders of #Estonia, #Latvia and #Lithuania, he began by blaming them for the war in Yugoslavia. It took them a few moments to realise he’d mixed up the Balkans and the Baltics. ⁦@SylvieKauffmann⁩ pic.twitter.com/HYQYpbqgGs

— Mark Lowen (@marklowen) November 10, 2018

The Baltic states lie in northern Europe, on the eastern coast of the Baltic Sea.

Around 1,000 miles away sits the Balkan region in southeastern Europe. It comprises states including Croatia, Bosnia-Herzegovina and Serbia.

Much of the region was incorporated into the state of Yugoslavia, a socialist state created after German occupying forces were ousted following World War II.

In the 1990s Yugoslavia disintegrated and the region was torn apart in a series of civil wars, culminating with the Kosovo war of 1998-1999.

missed this yesterday: according to Le Monde, when Trump hosted the leaders of the Baltic countries at the White House earlier this year he blamed them for the war in Yugoslavia, which uh took place in the Balkans pic.twitter.com/kd967AlWd6

— Matthew Champion (@matthewchampion) November 11, 2018

Although it’s not surprising that world geography isn’t Trump’s strong suit, this case is particularly notable considering Melania Trump is originally from the Balkans. The first lady was born in Slovenia, which gained independence in 1991 at the start of the Balkan wars. As Le Monde wrote, Trump remained “apparently uneducated in the matter by his wife, Melania, originally from the former Yugoslavia.”

The report comes with new tensions emerging this weekend between Trump and the U.S.’s traditional European allies. The president is in Europe this weekend for events marking the centenary of the end of the First World War.

On Friday, Trump attacked French president Emanuel Macron on Twitter, after the French leader said that Europe needed to take more responsibility for its own security.

Trump faced widespread criticism Saturday for canceling a visit to Belleau, where 2,000 U.S. Marines were killed in combat in 1918, because it was raining.

In a speech in Paris on Sunday, Macron criticized nationalism, with self-declared nationalist Trump sitting only feet away.

“Patriotism is the exact opposite of nationalism: nationalism is a betrayal of patriotism,” said Macron, at the Armistice Day commemoration under the Arc de Triomphe.

“By pursuing our own interests first, with no regard to others’, we erase the very thing that a nation holds most precious, that which gives it life and makes it great: its moral values.”