European Jews started wearing the yarmulke, or kippa, in the 17th and 18th centuries, turning the skullcap into a religious symbol. Pious Jews are expected to cover their heads, but the fabric isn't that important, and a hat or scarf is acceptable, too. Jewish Halacha law requires men and boys to cover their head when they pray, visit a synagogue or a Jewish cemetery or study the religion.

The miter is the ceremonial headdress worn by bishops, mainly in the Roman-Catholic Church. It goes back to the 11th century, with the tall, peaked hat deeply cleft on the sides and adorned with two ribbons at the back symbolizing the Old and the New Testaments.

Members of the Sikh faith, a monotheistic religion founded in India's northern Punjab region in the 15th century, wear a dastar. A dastar is usually worn by men, with orange being a popular color. Underneath the cloth headwear, which is re-knotted every morning, Sikh men let their hair grow freely.

In Farsi, the word chador means "tent," and that is what this garment worn by observant Muslim women in some parts of the Middle East resembles. Usually black, it covers a woman from the head down, hiding the shape of the body, revealing only the face. The chador is worn over a woman's regular clothing.

Nuns almost always wear a distinctive veil to complete their religious garment, the habit. Novices' veils are white, while professed nuns usually wear a black veil, or one in their habit's color. Depending on the religious order, veils come in different sizes and shapes. Some are elaborate and cover the woman's entire head; others are simply pinned to the sister's hair.

Is a woman's headscarf a religious headdress, or a symbol of oppression? In the West in particular, that continues to be a matter of heated debate. It is certainly the most well-known female head covering. Turkish women (as in this photo) tie headscarves differently from women in Arabic countries.

The ultra-Orthodox Hasidic Jewish community in New York has strict rules for married women, who are required to shave their hair and wear a wig, the "sheitel." In her 2012 bestseller memoir "Unorthodox," US author Deborah Feldman describes growing up in the ultra-religious group.

A bit of cloth, strips of cardboard and a tassel — voila, the birett, a head covering worn by Roman Catholic priests since the 13th century. In the Netherlands, Germany, Britain and France, the hat has four corners. In many other countries, it has three.

A bit of cloth, strips of cardboard and a tassle — voila, the birett, a head covering worn by Roman Catholic priests since the 13th century. In the Netherlands, Germany, Britain and France, the hat has four corners. In many other countries, it has three. If you remember the character Don Camillo (played by French actor Fernandel in a series of films in the 1950s and '60s), you know the hat!

The cotton scarf that can be up to 15 meters long is worn by Tuareg Berber Muslim men throughout western Africa. The tagelmust covers the head and is pulled over the mouth and nose against wind-born sand in the desert. The turban-style headdress is worn by adult men only. When indigo blue, the tagelmust's dye can rub off on the skin, hence the Tuareg being called the "blue men of the desert."

The Jewish shtreimel hat is made of velvet and has a wide fur trim, usually sable. Married men wear the hat on Jewish holidays and for religious festivities. The eye-catching headgear originated in Hasidic communities in southeastern Europe, a tradition that became nearly extinct in Europe after the Holocaust.

The Amish are a conservative Christian group in North America that originated in the tradition of the Anabaptist movement in Switzerland and southern Germany. The first Amish fled to the US in the early 18th century to escape religious persecution. They live simple lives, and shun modern technology and conveniences. The women wear plain bonnets; the men wear straw or felt hats.

Focusing on contemporary Muslim style, the exhibition "Contemporary Muslim Fashions" held at Frankfurt's Museum Angewandte Kunst was first shown in San Francisco. The show examines a branch of fashion that is often talked about, but which is rarely given a forum to present itself. Among the exhibits is this design made of silk and Swarovski crystals by Malaysian luxury designer Bernard Chandran.

The show also deals with Islamophobia: The First Amendment of the US Constitution is printed in Arabic on this bomber jacket. Among other things, the amendment lays out freedom of religion. The jacket was designed by Lebanese designer Celine Semaan Vernon. She came to Canada as a refugee with her parents at the end of the 1980s and then moved to the US.

Celine Semaan repeatedly uses her designs to make political statements. In 2017, for example, she designed her "banned" scarves. Some of the scarves feature a satellite photograph of the countries affected by US President Trump's travel ban. The model in this photo is Iranian-American political fashion blogger Hoda Katebi.

In addition to clothes, jackets and political scarves, the exhibition also deals with sports fashion. Among the exhibits are a Nike sports hijab and as well as this burkini designed by Shereen Sabet for her company Splashgear. The swimsuit has stirred controversy in different countries, especially in France where it was banned in some cities.

The Frankfurt exhibition includes pieces to demonstrate that modest fashion does not always mean women must cover. The young German-Turkish designer Feyza Baycelebi signed this creation, part of her collection "Die Lust an Verhüllung" — which translates as the desire or the pleasure to veil.

Naomi Afia from Vienna is another designer promoting empowerment through modest fashion. Her collection "Our Bodies Our Business" demonstrates the variety of styles one can adopt as a Muslim. "I wanted to make a statement for self-determination, a statement against constraints on what people should wear or not, whether these constraints come from one side or the other," the designer said.

Austrian designer Imen Bousnina featured her debut collection at Modest Fashion Weeks in 2018. First initiated in Dubai, such fashion events are now held in Istanbul, London and Jakarta as well. Modest fashion in Europe is mostly imported from Islamic countries like Turkey; this is something Bousnina hopes to change by creating her own designs.

Photographer Wesaam Al-Badr, who was born in Iraq but fled to the US with his family during the Gulf War, wanted to comment on the Western perception of the niqab through his series "Al-Kouture," showing women wearing designer scarves by brands like Chanel, repurposed as high-fashion pieces. It was a form of "soft protest," he says. Would the French would more readily accept a niqab signed Hermès?

This photo is part of the series "Occupied Pleasures," by Tanya Habjouqa. Her portraits shows how people occupy themselves in Israeli-occupied territories. Here girls play javelin right by the Israeli West Bank barrier. The photos won several awards, including a World Press Photo award in 2014.

Countless bloggers, influencers and fashion magazines are dedicated to the Muslim fashion world. On Instagram, so-called "hijabistas" celebrate the traditional headscarf as a fashion must-have. This aspect is also addressed in the exhibition "Contemporary Muslim Fashions," which can be seen in Frankfurt until September 15.