In about 1832, Baha'u'llah's older sister Sarih married Mirza Mahmud, a son of a minister of the Shah of Persia for the town of Yalrud, which is located near Baha’u’llah’s ancestral place, Takur in the northern province of Mazindaran. Three years later in about October 1835, Baha'u'llah himself, at the age of eighteen, married the sister of Mirza Mahmud, Asiyih Khanum who was then about sixteen years old. She was reported to have been beautiful, kind and caring. Baha’u’llah’s older sister had an active and supporting role in her Brother’s wedding arrangements.
This is how Bahiyyih Khanum, Asiyih Khanum’s daughter, recalled her mother many years later during a conversation with lady Blomfield, a Baha’i from the West who had gone on pilgrimage to Holy Land:
‘I wish you could have seen her as I first remember her, tall, slender, graceful, eyes of a dark blue --a pearl, a flower amongst women . . .
I have been told that even when very young, her wisdom and intelligence were remarkable. I always think of her In those earliest days of my memory as queenly in her dignity and loveliness, full of consideration for everybody, gentle, of a marvellous unselfishness, no action of hers ever faded to show the loving- kindness of her pure heart; her very presence seemed to make an atmosphere of love and happiness whenever she came, enfolding all comers In the fragrance of gentle courtesy.'
After the fall from power and death of Baha'u'llah's father in 1839, the family lost their home and Baha'u'llah had to rent a house in the 'Udlajan Quarter of Tehran for His wife, mother and most of His step-mothers and their children. It was here that the couple's surviving children were born (they had seven children in all but only three survived to adulthood). Their eldest surviving son was born in 1844 and was named ‘Abbas after his grandfather but is better known by the title he took later in life as ‘Abdu'l-Baha (the servant of Baha'u'llah). Next in 1846 came a daughter, named Fatimih Sultan Khanum, who in later years was known by the titles Bahiyyih Khanum and the Greatest Holy Leaf, and then in 1850 a son, Mirza Mehdi, who was later given the title the Purest Branch by Baha’u’llah.
(Adapted from 'Baha’u’llah: A Short Biography' by Moojan Momen)