The Epistle to the Son of the Wolf is the last major work of Baha'u'llah, founder of the Baha'i Faith, before his death in 1892. It is a letter written to a Muslim cleric, a violent opponent of the Baha'is who, along with his father (called by Baha'u'llah "the wolf"), also a Muslim cleric, had put to death a number of Baha'is. In this work Baha'u'llah quotes extensively from his own previously revealed scriptures. This makes a large portion of the work a summary of excerpts on critical concepts expressed in previous works in a condensed form. Two brothers Muhammad-Husayn Nahri and Muhammad-Hasan Nahri came from an aristocratic and established mercantile family in Isfahan. The Imam-Jum'ih of the city owed the brothers money and - when the two asked for a payment - he devised a plan to rid his debt. After confronting Shaykh Muhammad-Baqir, another influential Muslim cleric of Isfahan; and Sultan-Mas'ud Mirza, the son of Nasiri'd-Din Shah of this issue, the three devised a plan to imprison the brothers on account of their Baha'i religion. The two brothers were subsequently arrested, paraded around Isfahan with crowds jeering abuse, and publicly executed in a humiliating manner. Baha'u'llah was heartbroken by the death of the brothers - he had met the two whilst a prisoner in Adrianople. He eulogized the two, naming them the King and Beloved of Martyrs, and the Twin Shining Lights. Baha'u'llah wrote the book in around 1891 to the son of the shaykh, named Aqa Najafi, whom he denounced as the wolf - hence the title Epistle to the Son of the Wolf. Aqa Najafi was also known for his persecution of the Baha'is. Baha'u'llah calls for him to repent for his and his father's wrongdoings and to investigate the faith."