Baháʼu'lláh was the founder of the Baháʼí Faith. He was born in 1817 to Khadíjih Khánum and Mírzá Buzurg of Nur (in the province of Mazandaran), a Persian nobleman, and went on to be a leader in the Bábí movement, and then established the Baháʼí Faith in 1863. Baháʼu'lláh's family consists of his three wives and the children of those wives.

Titles of descendants One of Baháʼu'lláh's titles is Sadratu'l-Muntahá, which translates from Arabic as the tree beyond which there is no passing (a quote from Qurʼan 53:14). In this connection, Baháʼu'lláh entitled his descendants with terms relating to the Sadratu'l-Muntahá. His male descendants were given the title of Ag͟hsán (Arabic for "Branches") which in singular form is "G͟husn". In particular, four of his sons were given specific "branch" titles:

ʻAbdu'l-Bahá: G͟huṣn-i-Aʻẓam ( "The Most Great Branch"). Muhammad ʻAlí: G͟huṣn-i-Akbar, ( "The Greater Branch").G͟husn-i-Aʻẓam and G͟husn-i-Akbar can both be translated as "the great branch", "the greater branch" or "the most great branch". Aʻẓam carries a higher status in Arabic (see , or ), so Baháʼí authors and others translate ʻAbdu'l-Bahá's title as "Most Great" and Muhammad ʻAlí's title as "Greater" (Taherzadeh, 2000, p. 256.). The designations of G͟husn-i-Aʻẓam and G͟husn-i-Akbar are clear. (Browne, 1918, p. 61, & p. 85 ) Mihdí: G͟huṣn-i-Athar, ( "The Purest Branch"). Badíʻu'lláh: G͟husn-i-Anwar, ("The Most Luminous Branch").

His daughters were given the title of Varaqat (translated from Arabic as "Leaves"). Thus Baháʼu'lláh's eldest daughter, Bahíyyih (given name, Fatimih), was given the title of the Greatest Holy Leaf.

During Baháʼu'lláh's lifetime, he referred to his eldest son, Abbás, by terms such as "Sirru'lláh" (Mystery of God), or "Sarkár-i-Áqá" (the Master). After the death of Baháʼu'lláh, he chose the title "ʻAbdu'l-Bahá" (Servant of Bahá). Baháʼu'lláh did not give his descendants any direct right to the property of others.

Aghsán Aghṣán ("Branches") is a term in the literature of the Baháʼí Faith referring to the male descendants of Baháʼu'lláh.

It has particular implications not only for the disposition of endowments but also for the succession of authority following the passing of Baháʼu'lláh and of his son ʻAbdu'l-Bahá.

Baháʼí literature grants a special station to the members of the Aghṣán, indicating that Baháʼís should treat them with particular respect and courtesy, but does not grant them any administrative or spiritual authority within the Baháʼí Faith outside of those selected as successors to Baháʼu'lláh.

Ásíyih

Ásiyih was born in 1820 in the village of Yalrud, Mazandaran. Her father was Mirza Ismaʻil-i-Vazir, a powerful and wealthy Persian nobleman. Baháʼu'lláh addressed her as Navváb and the Most Exalted Leaf. She was chosen, at fifteen, to marry the young Baháʼu'lláh (18) based on her rare beauty, wealth, and piety. The family had pre-existing roots with Baháʼu'lláh's family by virtue of their influence in the royal court, which may have influenced the marriage arrangements. Three years after the elder sister of Baha'u'llah, Sarih Khanum, married Mirza Mahmud, the son of the Vazir-i-Yalrud, she who loved her winsome, vivacious, and beautiful sister-in-law, Ásiyih(15), requested her father, Mirza Buzurg-i-Nuri, to ask for Ásíyih's hand in marriage to Baha'u'llah(18).Ma'ani, Baharieh Rouhani (2008). Leaves of the Twin Divine Trees. Oxford, UK: George Ronald. P. 77. They married sometime between 24 September and 22 October 1835, in Tehran. Three of their children lived to adulthood. She died in 1886 in ʻAkká, and is buried on Mount Carmel within the vicinity of the Shrine of the Báb. Baháʼu'lláh named her his "perpetual consort" and her son as his vicar. Baháʼís regard the children of Ásíyih and Baháʼu'lláh to be the Baháʼí "holy family". Her children were:

ʻAbbas

Better known as ʻAbdu'l-Bahá, ʻAbbas was born in 1844 and died in 1921. He was the oldest child of Ásíyih and Baháʼu'lláh. He was variously referred to by Baháʼu'lláh as "Mystery of God", "The Master", "Perfect Exemplar" and "the Most Great Branch". After Baháʼu'lláh died on 29 May 1892, the Will and Testament of Baháʼu'lláh named ʻAbdu'l-Bahá as Centre of the Covenant, successor and interpreter of Baháʼu'lláh's writings. During his time as head of the religion, while still a prisoner of the Ottoman Empire, he met with many pilgrims and was in constant communication with Baháʼís around the world. After the 1908 Young Turks revolution freed all political prisoners in the Ottoman Empire, ʻAbdu'l-Bahá was freed from imprisonment and in 1910, with the freedom to leave the country, he embarked on a three-year journey to Egypt, Europe, and North America, spreading the Baháʼí message. On 27 April 1920, he was awarded a knighthood by the British Mandate of Palestine for his humanitarian efforts during World War I. ʻAbdu'l-Bahá died on 28 November 1921, and he is currently buried within one of the rooms at the Shrine of the Báb.

Bahíyyih

Bahíyyih Khánum was born in 1846 and was the eldest daughter of Baháʼu'lláh and Ásíyih Khánum. She was entitled the Greatest holy Leaf. She was particularly dear to her father and is seen within the Baháʼí Faith as one of the greatest women to have lived. She stood by and remained faithful to the Centers of the Covenant over years of infighting within Baháʼu'lláh's family that led to the expelling of many of them. She was given the position of acting head of the religion repeatedly when ʻAbdu'l-Bahá (during periods between 1910 and 1913), and Shoghi Effendi (during periods between 1922 and 1924), were absent from the Baháʼí World Centre in Haifa. Shoghi Effendi in particular felt her support during a difficult period following the death of ʻAbdu'l-Bahá. She died on 15 July 1932 and was buried in the Baháʼí gardens downhill from the Baháʼí Arc on Mount Carmel, under the Monument of the Greatest Holy Leaf raised for her at the Baháʼí World Centre.

Mihdí

Mírzá Mihdí was born in Tehran in 1848 and was entitled the Purest Branch. He died at the age of 22 on 23 June 1870 in ʻAkká after a fall through a skylight while he was preoccupied in prayer. The death is significant as Baháʼís believe that Baháʼu'lláh offered him the chance of being cured. However, he chose to use his life as a sacrifice so that the close imprisonment of the Baháʼís would end. Mírzá Mihdí was eventually buried alongside his mother in the gardens below the Baháʼí Arc on Mount Carmel in Haifa near his brother and sister.

Others Ásíyih bore at least four other children, all sons, but due to their early deaths little is known about them: Kázim who died sometime in Persia. Sádiq who died aged 3–4. ʻAlí Muhammad who died in Mazandaran at the age of 7 in 1852. ʻAlí Muhammad who was born and died in Baghdad at the age of 2.

Fatimih Baha'u'llah's second marriage happened under different circumstances. Fatimih, a first cousin of Baha'u'llah, was born in 1828 in Nur, Mazandaran, and was generally known as Mahd-i-'Ulya. Fatimih was married at fourteen to an influential cleric, Shaykh Muhammad Taqi, titled 'Allamah-i-Nuri in 1842. He was several decades older than she was. She seems to have been widowed shortly afterwards, perhaps aged sixteen. Since Fatimah had no children, she had no claim to her husband's estate and was effectively cast out of his family.Momen, Moojan (2021-11-26), "Bahá'u'lláh", The World of the Bahá'í Faith, London: Routledge, p. 41. (hbk) According to the custom of the time, a well-established male relative was expected to marry such a widow to preserve her honor and status. Fatimih's mother, Baha'u'llah's paternal aunt, had frequently reminded him of this responsibility, and her brother, Baha'u'llah's uncle, too, agreed.Ma'ani, Baharieh Rouhani (2008) Leaves of the Twin Divine Trees. p. 230. Oxford. UK It is reported that Baháʼu'lláh's aunt implored him to wed her widowed daughter, and he reluctantly agreed to do so. They married in 1849 in Tehran. She had six of Baháʼu'lláh's children, of whom four survived to adulthood. She was said to have been very jealous of and harbored great enmity towards ʻAbdu'l-Bahá. She died in 1904 and was later labelled a Covenant-breaker.

Her children are:

Samadiyyih Samadiyyih married Majdu'd-Din, who was the son of Aqay-i-Kalim, Baháʼu'lláh's brother; Majdu'd-Din was one of ʻAbdu'l-Bahá's greatest critics, and Samadiyyih and Majdu'd-Din were eventually declared Covenant-breakers. She died at age 49 in 1904/5 and her husband died at over one-hundred years of age in 1955.

Muhammad ʻAlí

Mírzá Muhammad ʻAlí Effendi was born in Baghdad in 1853. Baháʼu'lláh called him the "Greater Branch" and when Baháʼu'lláh declared ʻAbdu'l-Bahá his successor, he set that Muhammad ʻAlí was next in rank after him. Motivated by jealousy of ʻAbdu'l-Bahá he conspired to undermine his brother's leadership,: "Muhammad ‘Ali stole two cases with Bahalullah's seals and writings while ‘Abdul-Baha was washing his father's corpse. According to Badiullah, Muhammad ‘Ali searched the two cases for Bahalullah's testament which, however, was in the hands of ‘Abdul-Baha, who had received it prior to his father's death. After Baha'ullah's will and testament had been publicised and ‘Abdul-Baha had been invested as his successor, he asked Muhammad ‘Ali to return the seals. However, Muhammad ‘Ali refused to give them to him - an act by which he symbolically refused to acknowledge that religious authority had passed from his father to ‘Abdul-Baha. Muhammad ‘Ali is made responsible for ‘Abdul-Baha's continuous harassment by the Ottoman authorities and his renewed imprisonment in 1901. In order to take revenge for being left outside the leadership of the movement, he and his followers discredited him at the Ottoman authorities as secretly pursuing political objectives and striving for sedition and chaos within the Ottoman Empire and ultimately hoped that the Ottoman authorities would either exile ‘Abdul-Baha to another place or order his execution. Furthermore, he is accused of having interpolated the writings of his father in order to exalt his own position vis-a-vis his elder half-brother." but he was unable to gain extensive support from the Baháʼís. When ʻAbdu'l-Bahá died, his will went into great detail about how Muhammad ʻAlí had been unfaithful to the Covenant, labelling him a Covenant-breaker, and appointing Shoghi Effendi his successor instead. Muhammad ʻAlí was described by Shoghi Effendi as the "Arch-Breaker of Baháʼu'lláh's Covenant". Muhammad ʻAlí died in 1937. He is buried in one of the two private Bahá'í cemeteries in a square mausoleum covered with a white dome.

Ḍíyáʼu'lláh

Ḍíyáʼu'lláh (ضياء الله, alternate spelling: Zíyáʼu'lláh) was born August 15, 1864, in Edirne (Adrianople). He swayed in loyalty between his brothers, and was labelled a Covenant-breaker. He married Thurayyá Samandarí, daughter of Shaykh Kázim-i-Samandar and sister of Tarázʼu'lláh Samandarí, a Hand of the Cause of God. The marriage was childless, and according to Samandar's memoirs, Muhammad ʻAlí had prevented her from returning to him. He died on October 30, 1898, in Haifa. Ḍíyáʼu'lláh was initially buried next to his father at the Shrine of Baháʼu'lláh at the Mansion of Bahjí. However, having been declared a Covenant-breaker, Ḍíyáʼu'lláh's remains were later disinterred and moved.

Badíʻu'lláh