His father, Johann Wilhelm Bickell, was professor of canon law at the University of Marburg, and died (1848) as minister of justice of Hesse-Kassel (or Hesse-Cassel).
In 1862 Gustav became Privatdozent of Semitic and Indo-Germanic languages at Marburg, but the following year he went in the same capacity to the University of Giessen.
The finding of a clear testimony in favour of the Immaculate Conception in the hymns of Ephrem the Syrian, which he was transcribing in London, led him to enter the Catholic Church, 5 Nov., 1865.
After his conversion he entered the seminary of Fulda, where he was ordained priest on 22 September 1865.
[1] He then taught Semitic languages at the Academy of Münster, and in 1871 was appointed extraordinary professor.