Sa'd ibn al-Rabi' was killed at Uhud and his brother took everything; his widow brought their two daughters to Muhammad, and the Koran's inheritance verse followed

The hadith collections of al-Tirmidhi, Abu Dawud and Ibn Majah record the case. Sa'd ibn al-Rabi' was killed at Uhud. His widow brought their two daughters to Muhammad. She said their uncle had taken all of Sa'd's property and left them nothing, and that they would not be married unless they had money. Muhammad said God would decide. Ibn Kathir's commentary says this was one reason given for the revelation of Koran 4:11. Before Islam, he writes, Arabs gave inheritance to males and not to females. The verse set fixed shares: a son takes twice a daughter's share; two or more daughters share two-thirds; a wife takes an eighth if her husband leaves children. Muhammad sent word to the uncle: give Sa'd's two daughters two-thirds, give their mother one-eighth, and keep what is left. The uncle went from holding everything to holding the remaining five twenty-fourths. Al-Tirmidhi graded the report "hasan sahih"; the site that carries it labels it weak. The verse is still the basis of Islamic inheritance law, which most Muslim-majority states apply to family estates^†.