Excerpts from Books and Wikipedia
"The first to believe in the Bab. Called by Shoghi Effendi 'the lion-hearted.'" [Baha'i Glossary by Marzieh Gail, p. 36] "Mullá Husayn-i Bushru'i (1813–1849) titled Jináb-i-Bábu'l-Báb (Gate of the Gate), was a Persian religious figure, and the first Letter of the Living of the Bábí movement. He died at the Battle of Fort Shaykh Tabarsi, on February 2, 1849. His title of Bábu'l-Báb was bestowed upon him by the Báb." [Wikipedia]