RAQQA, Syria — When his factory was bombed in the northern Syrian city of Aleppo, the businessman considered two bleak options: remain at home and risk dying in the next airstrike, or flee like hundreds of thousands of others to a refugee camp in Turkey.

Instead, he took his remaining cash east and moved to a neighboring city, Raqqa, the de facto capital of the world’s fastest growing jihadist force. There he found a degree of order and security absent in other parts of Syria.

“The fighting in Syria will continue, so we have to live our lives,” said the businessman, who gave only a first name, Qadri, as he oversaw a dozen workers in his new children’s clothing factory in Raqqa.

Long before extremists rolled through Iraq and seized a large piece of territory, the group known as the Islamic State in Iraq and Syria, or ISIS, took over most of Raqqa Province, home to about a million people, and established a headquarters in its capital. Through strategic management and brute force, the group, which now calls itself simply the Islamic State, has begun imposing its vision of a state that blends its fundamentalist interpretation of Islam with the practicalities of governance.