Fashion designer Melih Kesmen reads inside a mosque in Witten. His modern brand of Islamic clothing, Styleislam, was born from outrage over the Mohammad caricatures in Denmark three years ago

Whether at his office, on the streets of Frankfurt, or on the music stage, rapper Fouad As-Idi, has no qualms wearing a T-shirt with a special message: “Terrorism has no religion.”

“The motives are super both for Muslims and non-Muslims,” says Mr. Idi, a Moroccan-Italian Frankfurter better known as his stage name, Sayfoudin “It’s a message that speaks to everybody.”

The T-shirt is a product of Styleislam, a new brand of Muslim fashion that has been sweeping through the streets of Europe. Mixing Islamic themes with hip-hop culture in a collection of 35 T-shirts, casual wear, and accessories for men and women, Styleislam products have one main message: Being Muslim and being modern go together.

“T-shirts are a bridge, they are a means to establish a dialogue with mainstream society,” says Melih Kesmen, Styleislam’s creator, whose parents left Turkey in the 1960s to help Germany rebuild its infrastructure after the traumas of World War II. “Our goal is to strengthen the identity of European Muslims, to say that we are a part and parcel of this society – and have been for a long time. And to say that being Muslim can be cool, too,” says Mr. Kesmen from Witten, an industrial city in northwestern Germany.

Styleislam was born out of Kesmen’s outrage at the Mohammad caricatures in Denmark three years ago. “I couldn’t believe that in the name of the freedom of expression, the world was bashing a religion,” says Kesmen. “It can’t be that we always have to be in the position to justify ourselves when only 1 percent of Muslims are radical.”

Unlike thousands of Muslims who resorted to violence to vent their frustration, Kesmen used his creativity, by designing a T-shirt with something special written on it: “I love my Prophet.”

No sooner was he out on the streets with his T-shirt that people started stopping him, asking questions, convincing him of the power of fashion in making people think, and of the existence of a market for his fashion.

Today, his idea has evolved into a designing firm with eight full-time employees selling Muslim fashion with Islamic themes in the world’s four corners, from the United States to Western Europe, from Canada to Turkey. Some T-shirts are for women. One, for instance, refers to the head scarf: “Hijab – my right. My choice. My life.” Others preach tolerance. “Jesus & Muhammad / Brothers in Faith.”

Styleislam sponsored the first tournament of Germany’s Muslim Basketball Association in Frankfurt last year. The players’ T-shirt reads: “Ball Against War!”

“But for us, it’s more important when ordinary people wear the T-shirts and walk around – in the subway, on the streets – when they make their presence visible in society,” Kesmen says.

“We are fighting against the ‘They and Us’ mentality. It is nonsense to say ‘They, the Muslims, and we, Europa,’ ” Kesmen says. “My message is that there is no contradiction in being European, German, and Muslim at the same time.”

One T-shirt at a time, his message seems to be heard.

Just the other day in Frankfurt, rapper Sayfoudin’s co-workers came in with a Styleislam T-shirt, too. It said, in big black letters, “Salam.”

“Salam,” for peace.