Why Melania Trump covers her head one day and not the next

US President Donald Trump, accompanied by first lady Melania Trump, smiles at Saudi King Salman (left) upon his arrival at a welcome ceremony at the Royal Terminal of King Khalid International Airport, Saturday, May 20, 2017, in Riyadh. Trump opened his first trip abroad since taking office, touching down Saturday in Saudi Arabia for a visit aimed at building stronger partnerships to combat terrorism in the region and moving past the controversies engulfing his young administration. (Photo by EVAN VUCCI / AP)

WASHINGTON — To cover up or not to cover up?

Melania Trump wore a veil to the Vatican on Wednesday to meet the Pope, but no head covering a few days earlier to meet the king of Saudi Arabia, a religiously conservative country where most women cover themselves up from head to toe.

Why the difference? The answer is a complicated mix of personal preference, diplomatic protocol and religious dictates.

Stephanie Grisham, a spokesperson for the US first lady, said the latter’s decision to wear a black lace veil known as a mantilla followed Vatican protocol that women having an audience with the Pope must wear long sleeves, formal black clothing and a veil to cover their head.

In Saudi Arabia, however, the government did not request that Melania Trump wear a head covering known as a hijab, or a headscarf, Grisham said.

The Vatican’s rules of attire are not strictly enforced. Many women, including high-ranking dignitaries, have visited the Pontiff with their heads uncovered, including German Chancellor Angela Merkel in 2015 and Aung San Suu Kyi, Myanmar’s top civilian leader, this month.

Most women wear veils out of respect. The US first lady is Catholic, which likely made accompanying US President Donald Trump for a meeting with the leader of the world’s more than 1 billion Roman Catholics all the more meaningful to her.

When a Vatican official handed her a rosary, the first lady immediately gave it to the Pope to bless. She spent time in front of a statue of the Madonna at the Vatican’s children’s hospital and laid flowers at its feet. She also prayed in the hospital chapel.

Every woman in the US delegation wore a veil, including Ivanka Trump, the president’s daughter who converted to Judaism before marriage.

Modestly dressed

In Saudi Arabia, the first lady dressed conservatively for her arrival on Saturday in the capital of Riyadh. She wore a long-sleeved, high-necked, black pantsuit that mimicked the loose, black robes, or abayas, that Saudi women and female residents wear.

Her attire during the two-day visit hewed to the protocol for high-level female visitors: modest dress, longer sleeves, higher necklines, pants and long dresses.

Ivanka Trump also dressed modestly, and left her head uncovered.

Most Western VIP women who visit Saudi Arabia don’t cover their heads, including British Prime Minister Theresa May and Merkel. Laura Bush and Michelle Obama also left their heads bare when they visited as first ladies. Then-citizen Donald Trump criticized Michelle Obama for doing so in 2015.

In Riyadh, Melania Trump didn’t visit any Muslim holy sites or mosques where head coverings and other steps such as removing one’s shoes would have been required.

Donald dons yarmulke

In Israel, the Trumps visited the Western Wall, the holiest site where Jews can pray. Donald Trump, who became the first US president to visit the wall while in office, donned a yarmulke—a skullcap—which is customary; the site keeps stacks of them for visitors to wear.

The president also wore a yarmulke at Yad Vashem, Israel’s Holocaust memorial, where it is not required. Trump likely wore one out of respect.

In keeping with Orthodox Jewish tradition, men and women pray separately at the wall. Ivanka Trump wore a black head covering to the wall, while Melania Trump wore no head covering. Many Orthodox Jewish women cover their hair as a sign of modesty.

At the Vatican, while Melania Trump strictly followed tradition and protocol by wearing black and a mantilla, other high-profile visitors have taken liberties with their attire.

‘Privilege du blanc’

In 2006, Cherie Blair, a practicing Catholic and wife of then British Prime Minister Tony Blair, violated protocol outright when she wore white for a meeting with Pope Benedict XVI.

Only royals are allowed the “privilege du blanc”—the so-called white privilege that dictates white outfits and white head coverings for queens and other royals when meeting the Pontiff.

In 1989, during the landmark audience between Mikhail Gorbachev and Pope John Paul II following the fall of the Berlin Wall, it was the Soviet leader’s wife, Raisa Gorbachev, who stole headlines: She wore a bright red dress. —AP