The House of Peace, those who live under Islam. Outsiders are to be brought in by submission. Some Muslims consider Christians and Jews “people of the book” and part of Dar al-Islam, but most consider them outsiders. A Muslim woman cannot marry anyone outside the house of Islam, and a Muslim man cannot marry anyone who isn’t among the people of book. Traditionally, Muslims subjugated lands they conquered by marrying their women, thus making their children Muslim.