Sharī'a court records (sijills) are legal documents that summarize discussions that took place in the courtroom. They also contain a wealth of detail on various aspects of Muslim society. Drawing on different sijills from nineteenth-century Palestine and fatwās of Khayr al-Dīn al-Ramlī, I examine the phenomenon of child marriage and the practice of khiyār al-bulūgh, literally "option of puberty". If a natural guardian contracts a marriage for a minor child, male or female, the child may not subsequently have the contract annulled. Whereas a boy enjoys the right to divorce his wife through the mechanism of talāq as soon as he reaches his majority, a girl who reaches her majority must approach the court if she wants to dissolve a marriage (faskh), and she may do so only if she was married while a minor by a non-natural guardian. In this case, she may exercise her right of khiyār al-bulūgh immediately upon reaching her legal majority, i.e., at the onset of her first menstruation. But she must make a public declaration of the occurrence of menstruation so that the persons who hear the declaration may serve as witnesses on her behalf.