Al-Zubayr bin Bakkar relates: To Umar (may Allah be pleased with him) were born Abdullah bin Umar, and his full sister Hafsah bint Umar, who was the wife of the Prophet (peace and blessings be upon him), and Abd al-Rahman the Elder. Their mother was Zaynab bint Maz'un bin Habib bin Wahb bin Hudhafah bin Jumah, who was one of the women emigrants, and before the Prophet (peace and blessings be upon him) she (Hafsah) had been married to Khunays bin Hudhafah al-Sahmi. Her father and her paternal uncle Zayd took part in Badr, and her maternal uncles Uthman and Qudamah, and her maternal cousins Abdullah and al-Sa'ib bin Uthman, also took part in Badr.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 19605