Mexican President Andres Manuel Lopez Obrador tore open a 500-year-old wound Monday when he said he had sent letters to the king of Spain and the pope urging them to apologize for the conquest of the Americas and the misdeeds committed in the name of the crown and the Church in the centuries of colonialism that followed.
The Spanish government responded with a blunt no, saying it "firmly rejects" the idea.
READ MORE Sorry not sorry: Spain rejects Mexico's demand for apology for colonial abuses
The Vatican, for its part, said it considered the matter closed, recalling on its website that a series of popes already apologized for the abuses committed in the name of evangelizing the indigenous peoples of the New World.
That includes Pope John Paul II in 1992, on the 500th anniversary of Christopher Columbus's arrival in the Americas, and Pope Francis on two occasions -- in Bolivia in 2015 and Mexico in 2016.
In Spain, the Mexican president's foray into the history books got swept up in the politics of a country gearing up for snap elections on April 28t, in which conservative parties are trying to portray Socialist Prime Minister Pedro Sanchez as a weak defender of national interests.
The leader of center-right party Ciudadanos, Albert Rivera, called the Mexican president's letter "an intolerable offense to the Spanish people."
Esteban Gonzalez Pons, a lawmaker in the European Parliament with the conservative Popular Party, said Lopez Obrador should "stop fighting" dead conquistadors.
And Arturo Perez-Reverte, one of Spain's most popular contemporary writers, said if the Mexican president "really believes what he says, he's a fool."
'More important business' Lopez Obrador said he was not trying to antagonize Spain.
"We're not going to get into a confrontation with the government of Spain... We are simply proposing an idea we think would help bring our peoples closer together," he told a press conference.
In Mexico, the most notable reaction to the president's remarks was apathy.
Many wondered why the leftist leader was not focusing on more pressing problems, such as rampant crime and corruption.
"Honestly, I think we have situations in this country that he should be concentrating on a little bit more," Tristan Velazquez, a 23-year-old government worker in Mexico City, told AFP.
Mexico and other Latin American countries already held raging debates over the legacy of colonialism in 1992, on the 500th anniversary of Columbus's arrival.
There was puzzlement over Lopez Obrador's decision to reopen to the topic in connection with another anniversary -- that of conquistador Hernan Cortes's first battle, waged on March 14, 1519, with the indigenous inhabitants of Centla.
"It wasn't great timing," said historian Lorenzo Meyer, of the College of Mexico.
"Mexico can't make anyone apologize," he told AFP.
"You can't do it by force. If you try, the only response you can expect is anger, is 'Who do you people think you are?'"
There were, however, events that took place during the Spanish conquest worth apologizing over, Meyer said.
Mesoamerica had an estimated population of 15 million to 30 million people when Cortes arrived with an army of several hundred men, carrying horses, swords, guns and smallpox -- all unknown in the New World at the time.
After a century of battles, massacres and plagues, an estimated one million to two million indigenous inhabitants remained.
"The demographic catastrophe of the conquest is clear," he said.
Mexico, which gained independence in 1821, has a complicated relationship with its colonial past.
The nation is the product of "mestizaje," the mixing of the Old and New Worlds. But it is a history tainted by violence, rape and oppression.
The angry reaction in Spain to Lopez Obrador's comments indicates the past is still problematic there, too, said Meyer.
"I don't understand the virulence of the Spanish response," he said. "It shows Spain hasn't gotten over it, either."
Other historians said there was no point in Spain and Mexico fighting over the past.
As author Francisco Martin Moreno told TV network MVS, Spain and Mexico "didn't even exist as such" 500 years ago.
By AFP's Yussel Gonzalez