Sayyiduna Muawiyah bin Abi Sufyan (may Allah be pleased with him) wrote (a letter) to Sayyiduna Zaid bin Thabit (may Allah be pleased with him) and asked about the inheritance of the grandfather. Sayyiduna Zaid bin Thabit (may Allah be pleased with him) wrote in reply that you asked me about the inheritance of the grandfather, and this is an issue in which the caliphs used to give rulings. I was present before the two caliphs before you (Sayyiduna Umar and Sayyiduna Uthman, may Allah be pleased with them), so with one brother they would give the grandfather half, and with two brothers, a third. Even if there were many brothers and sisters, they would not give the grandfather less than a third.