About April 10, 1848 the Báb was transferred to the fortress of Chihriq

Secret agents, however, charged to watch ‘Alí Khán, informed Hájí Mírzá Áqásí of the turn events were taking, whereupon he immediately decided to transfer the Báb to the fortress of Chihríq (about April 10, 1848), surnamed by Him the Jabal-i-Shadíd (the Grievous Mountain). There He was consigned to the keeping of Yahya Khán, a brother-in-law of Muhammad Sháh. 

- Shoghi Effendi  (Chapter 2, ‘God Passes By’)

Among the eager and devout pilgrims who were allowed to be admitted at the gates of the fortress was Mullá Husayn

Among them was the dauntless and indefatigable Mullá Husayn, who had walked on foot the entire way from Mashad in the east of Persia to Máh-Kú, the westernmost outpost of the realm, and was able, after so arduous a journey, to celebrate the festival of Naw-Rúz (1848) in the company of his Beloved. 

- Shoghi Effendi  (Chapter 2, ‘God Passes By’)

Despite severe restrictions the inhabitants of the village of Máh-Kú “were gradually subdued by the gentleness of the Báb, were chastened by His modesty, were edified by His counsels, and instructed by His wisdom” – including the warden of the fortress.

Secluded on the heights of a remote and dangerously situated mountain on the frontiers of the Ottoman and Russian empires; imprisoned within the solid walls of a four-towered fortress; cut off from His family, His kindred and His disciples; living in the vicinity of a bigoted and turbulent community who, by race, tradition, language and creed, differed from the vast majority of the inhabitants of Persia; guarded by the people of a district which, as the birthplace of the Grand Vizir, had been made the recipient of the special favors of his administration, the Prisoner of Máh-Kú seemed in the eyes of His adversary to be doomed to languish away the flower of His youth, and witness, at no distant date, the complete annihilation of His hopes. That adversary was soon to realize, however, how gravely he had misjudged both his Prisoner and those on whom he had lavished his favors. An unruly, a proud and unreasoning people were gradually subdued by the gentleness of the Báb, were chastened by His modesty, were edified by His counsels, and instructed by His wisdom. They were so carried away by their love for Him that their first act every morning, notwithstanding the remonstrations of the domineering ‘Alí Khán, and the repeated threats of disciplinary measures received from Tihrán, was to seek a place where they could catch a glimpse of His face, and beseech from afar His benediction upon their daily work. In cases of dispute it was their wont to hasten to the foot of the fortress, and, with their eyes fixed upon His abode, invoke His name, and adjure one another to speak the truth. ‘Alí Khán himself, under the influence of a strange vision, felt such mortification that he was impelled to relax the severity of his discipline, as an atonement for his past behavior. Such became his leniency that an increasing stream of eager and devout pilgrims began to be admitted at the gates of the fortress. 

- Shoghi Effendi  (Chapter 2, ‘God Passes By’)

No one was allowed to see the Báb for the first two weeks at Máh-Kú – other than His amanuensis and his brother

Upon His arrival in Máh-Kú, surnamed by Him Jabal-i-Básiṭ (the Open Mountain) no one was allowed to see Him for the first two weeks except His amanuensis, Siyyid Ḥusayn, and his brother. So grievous was His plight while in that fortress that, in the Persian Bayán, He Himself has stated that at night-time He did not even have a lighted lamp, and that His solitary chamber, constructed of sun-baked bricks, lacked even a door, while, in His Tablet to Muhammad Sháh, He has complained that the inmates of the fortress were confined to two guards and four dogs. . 

- Shoghi Effendi  (Chapter 2, ‘God Passes By’)