Wikipedia
Mullá Zaynul-Ábidín was born in the month of Rajab 1233 AH (May 1818 AD) in one of the villages of Najafábád Iran near Isfahán to a family of Muslim Clerics. He himself became a preacher at a mosque in Najafábád. In 1851, he became a Bábí (follower of The Báb), and began teaching his newfound faith in his hometown. It soon became a stronghold of the Bábí faith. in the mid-1850s, when Jináb-i-Bahá (later named Bahá'u'lláh) returned to Baghdad from his two-year absence in Sulaymáníyyih, Zaynul-Ábidín met him and became more strongly confirmed in his faith. When Bahá'u'lláh proclaimed himself to be the Promised One of God, for whom the Báb was himself a herald, Zaynul-Ábidín immediately became a Bahá'í (follower of Bahá) and settled in Baghdad transcribing holy writings. Bahá'u'lláh gave him the surname "Zaynul-Muqarrabín" which means "the Ornament of the Near Ones".
In 1870 the Bahá'ís of Baghdad were exiled to Mosul. Zaynul-Muqarrabín provided them with leadership and guidance and continued to transcribe the Tablets of Bahá'u'lláh that arrived from Akká on their way to Iran.
In Dhu'l-hijjah 1302 AH (Sept-Oct 1885 AD) Bahá'u'lláh gave him permission to come to Akká where he continued serving faithfully until the end of his life in 1903.