At the very birth of Islam, all Muslims were fairly equal under Allah, but that changed as time progressed. Despite allowances in the Quran, which, in theory, made women and men equal, patriarchy within the Islamic world continued to strengthen through the early centuries. Beginning around 634 with the second caliph Umar, the caliphs gradually made laws restricting women from associating with men, in prayer, and then in public. The wearing of veils became mandatory during Umar's reign, as did private prayer for women. The caliph Mansur ordered that a separate bridge be built for women in Baghdad. This growing separation was more easily enforced for the upper class than for the lower. Nevertheless, all women soon became subject to worse discrimination as old Arab cultural practices came back into favor, such as honor killing for sexual offenses. This abuse was justified, particularly in the Hadith, by the perception of women as vile temptresses and inferior to men. This perception and the stigma attached to it still exist in modern Islam.