In brief outline the narrative is this. For some while He wandered about in those districts. After the death of the late prince Muhammad _Sh_áh He returned to Tihrán, having in His mind [the intention of] corresponding and entering into relations with the Báb. The medium of this correspondence was the celebrated Mullá 'Abdu'l-Karím of Qazvín, who was the Báb's mainstay and trusted intimate. Now since a great celebrity had been attained for Bahá'u'lláh in Tihrán, and the hearts of men were disposed towards Him, He, together with Mullá 'Abdu'l-Karím, considered it as expedient that, in face of the agitation amongst the doctors, the aggressiveness of the greater part of [the people of] Persia, and the irresistible power of the Amír-Nizám, whereby both the Báb and Bahá'u'lláh were in great danger and liable to incur severe punishment, some measure should be adopted to direct the thoughts of men towards some absent person, by which means Bahá'u'lláh would remain protected from the interference of all men. And since further, having regard to sundry considerations, they did not consider an outsider as suitable, they cast the lot of this augury to the name of Bahá'u'lláh's brother Mírzá Yahyá.
By the assistance and instruction of Bahá'u'lláh, therefore, they made him notorious and famous on the tongues of friends and foes, and wrote letters, ostensibly at his dictation, to the Báb. And since secret correspondences were in process the Báb highly approved of this scheme. So Mírzá Yahyá was concealed and hidden while mention of him was on the tongues and in the mouths of men. And this mighty plan was of wondrous efficacy, for Bahá'u'lláh, though He was known and seen, remained safe and secure, and this veil was the cause that no one outside [the sect] fathomed the matter or fell into the idea of molestation, until Bahá'u'lláh quitted Tihrán at the permission of the King and was permitted to withdraw to the Supreme Shrines.
When He reached Ba_gh_dád and the crescent moon of the month of Muharram of the year [A.H. one thousand two hundred and] sixty-nine (which was termed in the books of the Báb "the year of 'after a while'" and wherein He had promised the disclosure of the true nature of His religion and its mysteries) shone forth from the horizon of the world, this covert secret, as is related, became apparent amongst all within and without [the society]. Bahá'u'lláh with mighty steadfastness became a target for the arrows of all amongst mankind, while Mírzá Yahyá in disguise passed his time, now in the environs and vicinity of Ba_gh_dád engaged for better concealment in various trades, now in Ba_gh_dád itself in the garb of the Arabs.