Donald Trump Jr. posted a photo on Instagram on Monday of him holding an AR-15-style rifle featuring an image of the kind of cross used during the Crusades, a series of medieval religious wars between Muslims and Christians. The magazine of the rifle is adorned with an illustration of former Democratic presidential candidate Hillary Clinton behind bars.

“Nice day at the range,” Trump Jr. wrote in his post, which also refers to the designer and seller of the gun.

It is unclear whether Trump Jr. owns the rifle.

The cross is Christianity’s most prominent symbol, appearing in Christian artwork and Western culture to commemorate the biblical account of Jesus’ crucifixion. The image of four crosses surrounding a larger one, shown in Trump Jr.’s post, is known as the Jerusalem cross and was used during the Crusades.

“At its best, the cross is a symbol of self-sacrifice and divine love. It has many different resonances for people,” said Robin M. Jensen, a theology professor at the University of Notre Dame who studies Christian art. “This is not what you put on a gun unless you’re saying Christians have a right to kill people who aren’t one of us.”

Andy Surabian, a spokesman for Trump Jr., said symbols “depicting various historical warriors” are common in gun culture. The symbols are common on gear and accessories, but adding them to guns is more niche and expensive. Base AR-15-style rifles can be bought for as little as $500, but the “Crusader” rifle retails for $2,125.

Surabian said the appearance of the Jerusalem cross was not a political statement.

“Don’s instagram post was strictly about him using a famous meme to mock Hillary Clinton, as he and many others have done on numerous occasions and will surely do again in the future, so long as it continues triggering humorless liberals,” Surabian said in a text message.

Trump Jr.’s post comes just days after the targeted U.S. killing of Qasem Soleimani, one of Iran’s top military figures. On Friday, President Trump spoke in front of a group of evangelicals in Florida, saying, “I really do believe we have God on our side,” the kind of reference used by Christian nationalists, who believe that God founded the United States to be a religious nation.

The magazine well of the rifle Trump Jr. holds is designed to look like a Crusader helmet and is made by Rare Breed Firearms as part of its Crusader label.

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What 3 words would you use to describe this Crusader?

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The Jerusalem cross grew out of the Crusades beginning in the early 11th century, according to Fredrick W. Bunce’s 2014 book, “Crosses, Christian and Otherwise: Their Form and Meaning." The four smaller crosses are said to represent the four gospels and the four corners of the world. Together, the five crosses are interpreted to represent the five wounds suffered by Christ at his crucifixion. That kind of cross is derived from the original Greek cross and is frequently employed in heraldry, according to Bunce.

In the right context, the Jerusalem cross is used as a symbol for Christian pilgrimage to the city, according to Dan Jones, a U.K.-based historian who wrote a book published last year on the Crusades. But that particular cross has been co-opted for all kinds of movements since. He noted how white supremacists during the Charlottesville protests and the New Zealand mass shooter have been inspired by images from the Crusades.

“At a time when tensions in the Middle East are running high, it’s an inflammatory time to run around with a gun with a crusader image on it,” Jones said.

A spokesman for the Southern Poverty Law Center said that Crusader imagery is frequently used by far-right extremists to invoke the notion that America and its citizens should retake land through violence and expel Muslim “invaders,” particularly in the United States and Middle East.

Trump Jr. is an avid hunter. Last year, he shot endangered sheep in Mongolia before he had approval from the government there.

Rare Breed Firearms appeared to provide the cross design on the rifle Trump Jr. posted, and Spike’s Tactical appeared to distribute it. Their companies do not indicate whether their owners have religious motivations, and no one from the companies returned requests for comment from The Washington Post on Monday.

Spike’s came under fire from some Muslim leaders in 2015 after it made a rifle with a Bible verse designed to repel Muslim terrorists. This time, Ibrahim Hooper, national communications director for the Council on American-Islamic Relations, said the rifle Trump Jr. is shown holding doesn’t appear to directly include an anti-Muslim message.

“A cross doesn’t offend me. It’s the context. It’s on a weapon,” Hooper said. “It’s a weapon that is similar to ones used in mass killings. The whole package sends the wrong message.”

In the Instagram photo, Trump Jr. poses with the rifle with the safety off and the selector switch on fire. Firearm safety norms discourage taking the safety off unless a weapon is pointed down range at a target and ready to be fired, which he is not doing in the photo. The bolt is pulled to the rear in one photo, and it is unclear whether there is any ammunition in the magazine, though it is probably empty. Trump Jr.’s finger is off the trigger.

A recent Axios-SurveyMonkey poll asked Republicans and Republican-leaning independents which Republican they would consider voting for in a theoretical 2024 general election, and 29 percent said Trump Jr. That put him second, behind Vice President Pence at 40 percent, and about even with former U.N. ambassador Nikki Haley at 26 percent, but above other hypothetical GOP candidates.

A 2017 Quinnipiac poll found 51 percent of registered voters overall had an unfavorable opinion of Trump Jr., 22 percent were favorable, and 25 percent had no opinion. Among Republican voters, a 54 percent majority had a favorable opinion of the president’s son, 14 percent were unfavorable, and 31 percent had no opinion.

Alex Horton and Emily Guskin contributed to this report.